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Effects of standardized ileal digestible lysine level on growth performance and economic return for 18 to 128 kg Duroc-sired pigs

Effects of standardized ileal digestible lysine level on growth performance and economic return... Translational Animal Science, 2022, 6, 1–13 https://doi.org/10.1093/tas/txac103 Advance access publication 12 August 2022 Non Ruminant Nutrition Effects of standardized ileal digestible lysine level on growth performance and economic return for 18 to 128 kg Duroc-sired pigs † †,1 † Rafe Q. Royall, Robert D. Goodband, Mike D. Tokach, † †, ‡ Joel M. DeRouchey, Jason C. Woodworth, and Jordan T. Gebhardt Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS 66506-0201, USA Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506-0201, USA Corresponding author: goodband@ksu.edu ABSTRACT The recent shift of the U.S. swine industry toward improved pork quality, such as color, marbling, and firmness, has led to increased use of Duroc-sired pigs in the marketplace. Our objective was to determine the standardized ileal digestible (SID) Lys requirement estimates for Duroc- sired (600 × 241, DNA, Columbus, NE) pigs from 18 to 128 kg BW. We conducted a series of experiments using corn–soybean meal-based diets with pigs allotted to 6 or 7 treatments in randomized complete block designs. In all experiments an equal number of barrows and gilts were used within a pen. In experiment 1, 300 pigs (initially 18.4 ± 0.50 kg) were used with 5 pigs per pen and 10 pens per treatment with 6 SID Lys levels from 1.00% to 1.50%. Increasing SID Lys increased (linear, P < 0.040) final BW, ADG, G:F, and Lys intake/kg of gain, and decreased (linear, P = 0.012) ADFI. In experiment 2, 608 pigs (initially 36.3 ± 0.91 kg) were used with 7 to 9 pigs per pen and 12 pens per treatment with 6 SID Lys levels from 0.80% to 1.20%. Increasing SID Lys increased (linear, P ≤ 0.036) ADG, G:F , and Lys intake/kg of gain. In experiment 3, 700 pigs (initially 53.2 ± 0.86 kg) were used with 8 to 10 pigs per pen and 12 pens per treatment with 6 SID Lys levels from 0.65% to 1.00%. Increasing SID Lys increased (linear, P < 0.001) final BW, ADG, and Lys intake/kg of gain, decreased (quadratic, P = 0.004) ADFI, and improved (quadratic, P < 0.001) G:F. In experiment 4, 616 pigs (initially 76.4 ± 1.25 kg) were used with 8 to 10 pigs per pen and 5, 6, or 11 pens per treatment with 7 SID Lys levels from 0.58% to 1.00%. Increasing SID Lys increased (linear, P ≤ 0.022) ADG, Lys intake per kilogram of gain, and G:F. In experiment 5, 679 pigs (initially 103.8 ± 1.32 kg) were used with 8 to 10 pigs per pen and 11 or 12 pens per treatment with 6 SID Lys levels from 0.43% to 0.78%. Increasing SID Lys increased (linear, P ≤ 0.043) final BW, ADG, and Lys intake per kilogram of gain, and improved (quadratic, P ≤ 0.032) G:F. Using results from all experiments, the quadratic equation of Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0002611 × BW – 0.0711037 × BW + 7.284 was developed to reflect the requirement for maximal growth performance from 18 to 128 kg BW. Maximal income over feed cost (IOFC) is best described by the quadratic equation: Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0001558 × BW − 0.04030769 × BW + 5.410. These data provide updated SID Lys estimates for Duroc-sired grow-finish pigs. LAY SUMMARY Lysine is typically the first limiting amino acid in corn–soybean meal-based swine diets, and as such, having an accurate estimate of lysine requirements for various genotypes is vitally important to optimize both growth performance and economic return. The focus of this research was to determine the standardized ileal digestible (SID) lysine requirement estimates of Duroc-sired pigs throughout the growing-finishing period. A series of five experiments were conducted where pigs were fed increasing levels of SID lysine at various weight ranges between 18 and 128 kg. Using the results of each individual experiment, we were able to develop equations to predict the Lys:calorie ratio required to maximize both growth performance and economic return. These equations can be utilized by swine production systems to optimize feeding programs for this genotype of pigs. Key words: amino acid, economics, growth, grow-finish pig, lysine Abbreviations: ADFI, average daily feed intake; ADG, average daily gain; BW, body weight; CP, crude protein; DM, dry matter; G:F, gain-to-feed; RCBD, randomized complete block design; SID, standardized ileal digestibility; STTD, standard total tract digestibility INTRODUCTION estimation of Lys requirements is crucial to maximize lean growth while optimizing feed cost in growing-finishing pigs. Improvements in modern swine genetics have resulted in Numerous factors have an impact on Lys requirements, such an increased potential for growth performance and pro- as genetics, environmental conditions, sex, and pig body tein accretion, which may cause a shift in dietary nutrient weight (Campbell and Taverner, 1988). Genetic suppliers requirements. As a result, it is important to continuously ana- provide estimates for amino acid requirements; however, lyze and reassess dietary nutrient requirements (O’Connell et validating these levels is necessary to optimize growth per- al., 2006). Lysine is typically the first limiting amino acid in formance and economic returns (De La Llata et al., 2001; corn–soybean meal-based swine diets, and as such an accurate Received May 6, 2022 Accepted July 21, 2022. Published by Oxford University Press for the American Society of Animal Science 2022. This work is written by (a) US Government employee(s) and is in the public domain in the US. 2 Royall et al. Main et al., 2008; Shelton et al., 2011). Additionally, it is im- increased within the industry by increasing both soybean portant to have an appreciation for the biological and eco- mean and L-Lys HCl. Previous research by Yen et al. (2005) nomic implications of feeding below, at, or above biological and Main et al. (2008), and many others have employed a sim- requirements throughout the grower-finishing period when ilar diet formulation strategy in determining Lys requirements developing feeding regimens (Main et al., 2008). of finishing pigs. In all experiments, pens of pigs were weighed, Recently, the U.S. swine industry has shifted toward an and feed disappearance was recorded approximately every 7 d emphasis for improved pork quality (color, marbling, and to determine ADG, ADFI, and G:F in all experiments. firmness), which has led to increased usage of Duroc-sired Experiment 1 pigs in the marketplace. Suzuki et al. (2003) observed that Duroc-sired pigs had excellent growth rates and intramus- A total of 300 pigs (initially 18.4 ± 0.50 kg to approximately cular fat content. Moreover, Soto et al. (2019) observed that 40 kg) were used in a 24-d study. There were 5 mixed-gender Duroc-sired late finishing pigs had 6% greater overall feed pigs per pen at a floor space of 0.30 m per pig. Pens of pigs intake compared with Pietrain-influence sired pigs reported were allotted by BW and randomly assigned to 1 of 6 dietary by Gonçalves et al. (2017). Therefore, the objective of these treatments with 10 replications per treatment in a randomized experiments was to determine the standardized ileal digestible complete block design (RCBD). Dietary treatments were (SID) Lys estimates for Duroc-sired finishing pigs from 18 to corn–soybean meal based and formulated to 1.00%, 1.10%, 128 kg with the intent of developing an SID Lys requirement 1.20%, 1.30%, 1.40%, or 1.50% SID Lys containing 0.25%, estimate curve for this genotype. 0.30%, 0.35%, 0.40%, 0.45%, and 0.50% L-Lys HCl, re- spectively, with other feed-grade AAs added as necessary to maintain ratios relative to Lys (Table 1). MATERIALS AND METHODS Experiment 2 General A total of 608 pigs (initially 36.3 ± 0.91 kg to approximately The Kansas State University Institutional Animal Care and Use 54 kg) were used in two consecutive groups of approximately Committee approved the protocol used in these experiments. 300 pigs with the group 1 study lasting 14-d and group 2 All experiments were conducted at the Kansas State University lasting 21 d. There were 7 to 9 mixed gender pigs per pen at a Swine Teaching and Research Center in Manhattan, KS. The floor space of 0.74 m per pig. Pigs were allotted by BW and facilities were totally enclosed and environmentally regulated. randomly assigned to 1 of 6 dietary treatments in an RCBD. In experiment 1, each pen (1.21 × 1.21-m) was equipped with a The dietary treatments included 6 SID Lys concentrations 4-hole, dry self-feeder, and a nipple waterer. Pens were located (0.80%, 0.88%, 0.96%, 1.04%, 1.12%, and 1.20%), with over a metal tri-bar floor with a 1.21-m pit underneath for 12 replications per treatment. manure storage. In experiments 2, 3, 4, and 5, each pen was equipped with a 2-hole dry, single-sided feeder (Farmweld, Experiment 3 Teutopolis, IL) and a 1-cup waterer, and adjustable gates to A total of 700 pigs (initially 53.2 ± 0.86 kg to approximately allow 0.74 m per pig. Pens were located over a completely 75 kg) were used in two consecutive groups of approximately slatted concrete floor with a 1.21-m pit underneath for ma - 350 pigs. Each study lasted 21 d. There were 8 to 10 pigs per nure storage. A robotic feeding system (FeedPro; Feedlogic pen with similar numbers of barrows and gilts in each pen. Corp., Wimar, MN) was used to deliver and record daily feed Pens of pigs were allotted by BW and randomly assigned to additions to each individual pen. Pigs were provided ad lib- 1 of 6 dietary treatments in a RCBD. The dietary treatments itum access to water and feed in meal form throughout the included 6 SID Lys concentrations (0.65%, 0.72%, 0.79%, experiments. Complete diets were manufactured at Hubbard 0.86%, 0.93%, and 1.00%), with 12 replications per Feeds, Beloit, KS for each experiment. All experimental diets treatment. were corn–soybean meal based. Ingredient nutrient composi- tion and SID AA coefficients were derived from NRC (2012), Experiment 4 except for NE of soybean meal which was set at 100% that A total of 616 pigs (initially 76.4 ± 1.25 kg to approximately of corn (Cemin et al., 2020). In experiment 1, six individual 106 kg) were used in two consecutive groups of approximately diets were manufactured (Table 1). In experiments 2, 3, 4, and 300 pigs. Each study lasted 21 d. There were 8 to 10 mixed 5, two diets were formulated to 0.80 and 1.20, 0.65 and 1.00, gender pigs per pen with similar numbers of barrows and gilts 0.58 and 1.00, and 0.43% and 0.78% SID Lys, respectively. placed in each pen. Pens of pigs were allotted by BW and ran- These dietary treatments were blended via a robotic feeding domly assigned to 1 of 7 dietary treatments in a RCBD. The system to establish the range of SID Lys levels in each experi- dietary treatments included 7 SID Lys concentrations (0.58%, ment (Tables 2 and 3). 0.65%, 0. 72%, 0.79%, 0.86%, 0.92%, and 1.00%), with 11 In each experiment, Duroc-sired pigs (600 × 241, DNA, replications for the 0.65%, 0.72%, 0.79%, 0.86%, and 0.92% Columbus NE) were used to estimate the SID Lys requirement. SID Lys treatments; 6 replications for the 0.58% SID Lys treat- Barrows and gilts were penned together with gender equalized ment; and 5 replications for the 1.00% SID Lys treatment. by pen or block for each experiment. For all experiments, ratios of other AAs to Lys were maintained well above re- Experiment 5 quirement estimates to ensure that Lys was the first-limiting A total of 679 pigs (initially 103.8 ± 1.32  kg to approxi- AA. Although the increase in dietary Lys was brought about mately 128 kg) were used in two consecutive groups of ap- by increasing the ratio of soybean meal to corn which also proximately 330 pigs. Each study lasted 21 and 28 d. There increased the CP content of the diet, Lys was the first limiting were 8 to 10 mixed gender pigs per pen with similar num- AA. This formulation strategy was used to make the results bers of barrows and gilts placed in each pen. Pens of pigs more translational to application, as SID Lys is typically were allotted by BW and randomly assigned to 1 of 6 dietary Lysine requirement of grow-finish pigs 3 Table 1. Diet composition in experiment 1 (as-fed basis) SID Lys, % Item 1.00 1.10 1.20 1.30 1.40 1.50 Ingredient, % Corn 69.40 66.55 63.67 60.81 57.93 55.13 Soybean meal, 46.5% CP 25.61 28.11 30.61 33.11 35.61 38.11 Corn oil 2.00 2.25 2.50 2.75 3.00 3.20 Limestone 1.00 1.00 0.98 0.98 0.95 0.95 Monocalcium P, 21% P 0.70 0.65 0.65 0.60 0.60 0.55 Sodium chloride 0.50 0.50 0.50 0.50 0.50 0.50 L-Lys-HCl 0.25 0.30 0.35 0.40 0.45 0.50 DL-Met 0.07 0.11 0.15 0.19 0.23 0.26 L-Thr 0.08 0.11 0.14 0.17 0.20 0.23 L-Trp 0.01 0.01 0.02 0.02 0.03 0.03 L-Val 0.00 0.02 0.05 0.08 0.11 0.15 Vitamin premix with phytase 0.25 0.25 0.25 0.25 0.25 0.25 Trace mineral premix 0.15 0.15 0.15 0.15 0.15 0.15 Total 100 100 100 100 100 100 Calculated analysis SID AA, % Lys, % 1.00 1.10 1.20 1.30 1.40 1.50 Ile:Lys 65 63 61 59 58 57 Leu:Lys 140 132 126 120 116 112 Met:Lys 32 34 35 36 37 37 Met and Cys:Lys 58 58 58 58 58 58 Thr:Lys 63 63 63 63 63 63 Trp:Lys 19.2 19.1 19.1 19.1 19.0 19.0 Val:Lys 71 70 70 70 70 70 His:Lys 43 41 40 39 38 37 Total Lys, % 1.13 1.23 1.34 1.45 1.55 1.65 NE, kcal/kg 2,553 2,553 2,553 2,553 2,553 2,553 SID Lys:NE, g/Mcal 3.92 4.31 4.70 5.09 5.48 5.88 SID Lys:CP, % 5.47 5.69 5.88 6.05 6.20 6.34 CP, % 18.3 19.3 20.4 21.5 22.6 23.7 Ca, % 0.68 0.68 0.68 0.68 0.68 0.68 P, % 0.51 0.51 0.52 0.52 0.53 0.53 STTD P, % 0.40 0.40 0.40 0.40 0.40 0.40 Diets were fed from 18.4 to 40.2 kg BW. Ronozyme Hiphos (GT) 2700 (DSM Nutritional Products, Inc, Parsippany NJ), provided 1248 phytase units (FYT/kg), for an estimated release of 0.12% STTD P. Provided per kilogram of premix: 1,653,465 IU Vitamin A, 661,386 IU Vitamin D , 17,637 IU Vitamin E, 1323 mg Vitamin K, 13 mg Vitamin B , 3 12 19,842 mg niacin, 11,023 mg pantothenic acid, 3,306 mg menadione. Provided per kilogram of premix: 11 g Cu, 0.2 g I, 73 g Fe, 22 g Mn, 0.2 g of Se, 73 g Zn. Ingrdient values and SID coefficients were derived from NRC (2012). treatments in a RCBD. The dietary treatments included 6 SID beginning of each trial. Diet samples were stored at −20 °C Lys concentrations (0.43%, 0.50%, 0.57%, 0.64%, 0.71%, until they were homogenized, subsampled, and submitted for and 0.78%), with 12 replications for the 0.43%, 0.50%, analysis of AA profile (method 994.12; AOAC International, 0.57%, 0.71%, and 0.78% SID Lys treatments, and 11 2012) conducted by Ajinomoto Animal Nutrition North replications for the 0.64% SID Lys treatment. America, Inc. (Eddyville, IA). Results of laboratory analysis indicated total nutrient profiles were consistent with expected diet formulation values. Chemical Analysis A sample of each diet in experiment 1 and from the lowest Economic Analysis and highest SID Lys, % diets in experiments 2, 3, 4, and 5 was submitted for AA profile ( Tables 4 and 5). In experi- For the economic analysis, feed cost/pig, feed cost/kg gain, ment 1, representative diet samples were obtained from every revenue per pig, and IOFC were calculated for high- and third bag of feed. In experiments 2, 3, 4, and 5, diet samples low-priced diets. High-priced diet costs were determined were taken from 6 feeders per dietary treatment 3 d after the using the following ingredient prices: corn = $6.00/bushel 4 Royall et al. Table 2. Diet composition experiment 2 and 3 (as-fed basis) Table 3. Diet composition experiment 4 and 5 (as-fed basis) experiment 2 experiment 3 experiment 4 experiment 5 1 2 1 2 SID Lys, % SID Lys, % SID Lys, % SID Lys, % Item 0.80 1.20 0.65 1.00 Item 0.58 1.00 0.43 0.78 Ingredient, % Ingredient, % Corn 78.62 64.75 83.12 71.87 Corn 85.26 71.87 87.36 81.71 Soybean meal, 46.5% CP 16.62 31.13 13.15 24.69 Soybean meal, 46.5% CP 10.94 24.69 10.19 14.90 Corn oil 1.65 1.00 1.40 1.00 Corn oil 1.50 1.00 0.40 0.90 Limestone 1.00 0.98 0.80 0.78 Limestone 0.80 0.78 0.80 0.80 Monocalcium P, 21% P 0.90 0.70 0.58 0.43 Monocalcium P, 21% P 0.60 0.43 0.55 0.50 Sodium chloride 0.50 0.50 0.50 0.50 Sodium chloride 0.50 0.50 0.50 0.50 L-Lys-HCl 0.28 0.33 0.19 0.28 L-Lys-HCl 0.17 0.28 — 0.30 DL-Met 0.03 0.13 0.02 0.10 DL-Met — 0.10 — 0.05 L-Thr 0.08 0.12 0.04 0.11 L-Thr 0.03 0.11 — 0.11 L-Trp 0.02 0.01 0.01 0.01 L-Trp — 0.01 — 0.02 L-Val 0.01 0.06 0.01 0.05 L-Val — 0.05 — 0.02 3 3 Vitamin premix with phytase 0.15 0.15 0.10 0.10 Vitamin premix with phytase 0.10 0.10 0.10 0.10 4 4 Trace mineral premix 0.15 0.15 0.10 0.10 Trace mineral premix 0.10 0.10 0.10 0.10 Total 100 100 100 100 Total 100 100 100 100 5 5 Calculated analysis Calculated analysis SID AA, % SID AA, % Lys, % 0.80 1.20 0.65 1.00 Lys, % 0.58 1.00 0.43 0.78 Ile:Lys 62 62 68 64 Ile:Lys 70 64 92 60 Leu:Lys 148 128 171 139 Leu:Lys 183 139 245 148 Met:Lys 31 34 33 35 Met:Lys 33 35 44 33 Met and Cys:Lys 58 58 65 61 Met and Cys:Lys 67 61 89 60 Thr:Lys 63 63 66 65 Thr:Lys 66 65 81 66 Trp:Lys 19 19 19 19 Trp:Lys 18 19 24 19 Val:Lys 72 72 80 75 Val:Lys 82 75 109 72 His:Lys 44 41 49 43 His:Lys 51 43 68 43 Total Lys, % 0.91 1.34 0.75 1.13 Total Lys, % 0.67 1.13 0.52 0.88 NE, kcal/kg 2,698 2,698 2,698 2,703 NE, kcal/kg 2,698 2,703 2,577 2,579 SID Lys:NE, g/Mcal 2.96 4.45 2.41 3.70 SID Lys:NE, g/Mcal 2.15 3.70 1.57 3.02 SID Lys:CP, % 5.42 5.79 4.87 5.51 SID Lys:CP, % 4.67 5.51 3.57 5.47 CP, % 14.8 20.7 13.4 18.1 CP, % 12.4 18.1 12.1 14.3 Ca, % 0.67 0.67 0.51 0.51 Ca, % 0.51 0.51 0.50 0.50 P, % 0.52 0.54 0.43 0.45 P, % 0.43 0.45 0.42 0.43 STTD P, % 0.40 0.40 0.32 0.32 STTD P, % 0.32 0.32 0.31 0.31 1 1 Diets were fed from 36.3 to 54.2 kg BW.The twodiets were blended to Diets were fed from 76.4 to 99.1 kg BW. The two diets were blended to create intermediate treatment diets containing 0.88, 0.96, 1.04, and 1.12% create intermediate treatment diets containing 0.65%, 0.72%, 0.79%, SID Lys, respectively. 0.86%, and 0.93% SID Lys, respectively. 2 2 Diets were fed from 53.2 to 74.2 kg BW.The twodiets were blended to Diets were fed from 103.8 to 127.3 kg BW. The two diets were blended to create intermediate treatment diets containing 0.72, 0.79, 0.86, and 0.93% create intermediate treatment diets containing 0.50%, 0.57%, 0.64%, and SID Lys, respectively. 0.71% SID Lys, respectively. 3 3 Ronozyme Hiphos (GT) 2700 (DSM Nutritional Products, Inc, Ronozyme Hiphos (GT) 2700 (DSM Nutritional Products, Inc., Parsippany NJ), provided 748 or 500 phytase units (FYT/kg), for an Parsippany NJ), provided 500 phytase units (FYT/kg), for an estimated estimated release of 0.10 or 0.09% STTD P, in experiments 2 and 3, release of 0.09% STTD P. Provided per kilogram of premix: 1,653,465 IU respectively. Provided per kilogram of premix: 1,653,465 IU Vitamin A, vitamin A, 661,386 IU vitamin D , 17,637 IU vitamin E, 1323 mg vitamin 661,386 IU Vitamin D , 17,637 IU Vitamin E, 1323 mg Vitamin K, 13 mg K, 13 mg vitamin B , 19,842 mg niacin, 11,023 mg pantothenic acid, 3 12 Vitamin B , 19,842 mg niacin, 11,023 mg pantothenic acid, 3,306 mg 3,306 mg menadione. menadione. Provided per kilogram of premix: 11 g Cu, 0.2 g I, 73 g Fe, 22 g Mn, 0.2 g Provided per kilogram of premix: 11 g Cu, 0.2 g I, 73 g Fe, 22 g Mn, 0.2 g of Se, 73 g Zn. of Se, 73 g Zn. Ingrdient values and SID coefficients were derived from NRC (2012). Ingrdient values and SID coefficients were derived from NRC (2012). ($236/tonne); soybean meal = $440/tonne; L-Lys at $1.76/kg; DL-Met at $5.51/kg; L-Thr at $2.65/kg; L-Trp at $11.02/kg; feed intake × diet cost ($/kg). Feed cost/kg of gain was calcu- and L-Val at $8.82/kg. Low-priced diet costs were determined lated using feed cost/pig divided by total gain. Revenue per using the following ingredient prices: corn = $3.00/bushel pig was determined for both a high and a low price by total ($118/tonne); soybean meal = $330/tonne; L-Lys at $1.43/kg; gain × $1.46/kg live gain, or total gain × $0.99/kg live gain, DL-Met at $3.75/kg; L-Thr at $1.87/kg; L-Trp at $6.61/kg; respectively. Income over feed cost was calculated using rev- and L-Val at $5.51/kg. Feed cost/pig was determined by total enue/pig—feed cost/pig. Lysine requirement of grow-finish pigs 5 Statistical Analysis lowest breakpoint suggested by the dose response models (ADG or G:F) was selected. In experiment 4, the midpoint Data were analyzed as an RCBD for a one-way ANOVA between the two suggested breakpoints was used. In exper- using the lmer function from the lme4 package in R Studio iment 5, the highest breakpoint suggested by the dose–re- (Version 3.5.2, R Core Team; Vienna, Austria) with pen sponse models was selected. The suggested requirement for serving as the experimental unit, pen average BW as blocking maximum growth performance from each experiment was factor, and treatment as fixed effect. Dose–response curves used to develop the regression equation. For economic re- were evaluated using linear (LM), quadratic polynomial turn, the highest breakpoint suggested by the dose–response (QP), and broken-line linear (BLL) models. For each re- models was used to develop the regression equation. These sponse variable, the best-fitting model was selected using curves describe the Lys:calorie ratio that best met biological the Bayesian Information Criterion (BIC). A decrease in BIC requirements for growth performance and optimized IOFC greater than 2.0 among models for a particular response in this series of trials (Figure 1) criterion was considered an improved fit. Results were considered significant with P ≤ 0.05 and were considered marginally significant with P ≤ 0.10. The predicted require- RESULTS ment for maximum growth performance and economic re- Experiment 1 turn found from dose response curves in each study were used to develop regression equations to predict the overall In 18- to 40-kg pigs, increasing SID Lys increased d 24 BW Lys:calorie ratio required for maximum growth perfor- (linear, P ≤ 0.04; Table 6). Overall ADG increased with mance and economic return. In experiments 1, 2, and 3, the increasing SID Lys (linear, P = 0.003). Pigs fed increasing SID Lys had decreased (linear, P = 0.012) ADFI from d 0 to 24. An improvement for overall G:F (linear, P < 0.001) Table 4. Amino acid analysis of diets (experiment 1; as-fed basis) was observed with increasing SID Lys. Daily SID Lys intake and Lys intake per kg of gain increased (linear, P < 0.001) SID Lys, % with increasing SID Lys. For economic analysis, feed cost and feed cost per kg of gain increased (linear, P < 0.001), Item 1.00 1.10 1.20 1.30 1.40 1.50 while total revenue tended to decrease (linear, P = 0.074) Amino acid analysis, % with increasing SID Lys at both high and low ingredient Lys 1.16 1.30 1.34 1.48 1.52 1.64 pig prices. At high ingredient and pig prices, there was no evidence of significant difference ( P > 0.10) for IOFC. Ile 0.74 0.81 0.76 0.87 0.90 0.95 However, at low ingredient and pig prices, increasing SID Met 0.35 0.40 0.38 0.45 0.50 0.53 Lys decreased (linear, P = 0.048) IOFC, with pigs fed diets Met + Cys 0.64 0.71 0.70 0.80 0.83 0.89 containing 1.10% SID Lys having the greatest numeric Thr 0.79 0.88 0.90 1.02 1.05 1.11 IOFC. Trp 0.24 0.25 0.28 0.31 0.31 0.33 Dose–response curves were evaluated for overall growth Val 0.83 0.91 0.88 1.00 1.07 1.14 performance, and when modeling ADG, the LM and QP His 0.48 0.51 0.50 0.55 0.55 0.59 models resulted in a comparable fit. The QP model equation Phe 0.98 1.04 1.02 1.12 1.13 1.17 was: ADG = −0.282148 × (SID Lys, %) + 0.797053 × (SID Lys, %) + 0.339, with maximum ADG estimated at 1.41% 1 rd Diet samples were taken from every 3 bag of feed 7 d after the beginning SID Lys (Supplementary Figure S1A). For the LM, maximum of the trial and stored at -20°C. Values are reported on a total analyzed ADG was predicted above 1.50% SID Lys. For G:F, the LM basis. Composite sample was submitted to Ajinomoto Heartland Inc. (Eddyville, resulted in the best fit, and predicted maximum feed efficiency IA) for amino acid analysis. above 1.50% SID Lys (Supplementary Figure S1B). Table 5. Amino acid analysis of diets (experiment 2, 3, 4, and 5; as-fed basis) experiment 2 experiment 3 experiment 4 experiment 5 SID Lys, % SID Lys, % SID Lys, % SID Lys, % Item 0.80 1.20 0.65 1.00 0.58 1.00 0.43 0.79 Amino acid analysis, % Lys 0.95 1.26 0.83 1.19 0.78 1.18 0.55 1.15 Ile 0.58 0.80 0.52 0.74 0.49 0.75 0.48 0.75 Met 0.25 0.41 0.22 0.35 0.19 0.33 0.23 0.34 Met + Cys 0.43 0.69 0.45 0.64 0.39 0.61 0.44 0.63 Thr 0.59 0.76 0.49 0.72 0.44 0.65 0.46 0.73 Trp 0.17 0.25 0.15 0.22 0.12 0.22 0.14 0.24 Val 0.69 0.93 0.64 0.87 0.59 0.87 0.61 0.86 His 0.43 0.56 0.40 0.53 0.39 0.53 0.31 0.47 Phe 0.81 1.05 0.74 0.98 0.68 1.01 0.62 0.94 Diet samples were taken from 6 feeders 3 d after the beginning of the trial and stored at -20°C. Values are reported on a total analyzed basis. Composite sample was submitted to Ajinomoto Heartland Inc. (Eddyville, IA) for amino acid analysis. 6 Royall et al. When modeling IOFC at high ingredient and pig prices, the and pig prices, the LM and BLL models had a similar fit to LM model resulted in the best fit and predicted the SID Lys re - maximize IOFC. The LM estimated maximum IOFC at less quirement to achieve maximum IOFC was at less than 1.00% than 1.00% SID Lys, while the BLL model predicted similar (Supplementary Figure S1C). Meanwhile, at low ingredient IOFC from 1.00 to 1.12% SID Lys with a reduction in IOFC when SID Lys increased past 1.12% (Supplementary Figure S1D). Experiment 2 In 36 to 54 kg pigs, increasing SID Lys did not significantly affect (P > 0.10) final BW ( Table 7). However, ADG increased (linear, P = 0.036) with increasing SID Lys, while there was no observed difference (P > 0.10) in ADFI. As a result, increasing SID Lys increased (linear, P < 0.001) G:F. Daily SID Lys intake and Lys intake per kg of gain increased (linear, P < 0.001) with increasing SID Lys. For economic analysis, feed cost and feed cost per kg of Figure 1. Optimal Lys:calorie ratio (g of Lys/Mcal of NE) prediction gain increased (linear, P < 0.002), and revenue tended to equations were developed for maximum growth performance and IOFC for 18 to 128 kg pigs using our interpretation of 5 trials conducted to increase (linear, P = 0.060) with increasing SID Lys at both determine the maximum SID Lys, % for Duroc-sired pigs (600 × 241, high and low ingredient and pig prices. At high ingredient and DNA) fed in a university research environment. Barrows and gilts were pig prices, there was no evidence of difference (P > 0.10) for penned together with gender equalized by block. To maximize growth IOFC. However, at low ingredient and pig prices, increasing performance, the quadratic equation is Lys:calorie ratio, g of SID Lys/ SID Lys tended to decrease (linear, P = 0.097) IOFC, with Mcal of NE = 0.0002611 × BW – 0.0711037 × BW + 7.284. To maximize pigs fed diets containing 0.88% or 0.96% SID Lys having the IOFC, the quadratic equation is Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0001558 × BW − 0.04030769 × BW + 5.410. greatest numeric IOFC. Table 6. Effects of increasing SID Lys on growth performance of pigs weighing 18 to 40 kg (experiment 1) SID Lys, % P = Item 1.00 1.10 1.20 1.30 1.40 1.50 SEM Linear Quadratic BW, kg d 0 18.4 18.5 18.4 18.4 18.4 18.4 0.50 0.918 0.863 d 24 39.0 39.9 39.9 39.6 40.1 40.2 0.86 0.040 0.537 Overall (d 0to24) ADG, g 844 889 895 888 894 907 17.0 0.003 0.166 ADFI, g 1,477 1,468 1,472 1,429 1,445 1,411 31.2 0.012 0.676 G:F, g/kg 572 605 609 622 620 643 6.4 < 0.001 0.212 SID Lys g/d 14.74 16.12 17.63 18.53 20.19 21.12 0.386 < 0.001 0.470 SID Lys g/kg gain 17.46 18.15 19.69 20.87 22.59 23.28 0.218 < 0.001 0.719 Economics, $ High ingredient and pig prices Feed cost/pig 11.91 12.49 12.73 12.92 13.47 13.64 0.314 < 0.001 0.702 Feed cost/kg gain 0.583 0.573 0.592 0.602 0.628 0.625 0.0064 < 0.001 0.272 Total revenue/pig 29.82 31.85 31.37 31.33 31.32 31.83 0.689 0.074 0.265 IOFC 17.91 19.36 18.64 18.41 17.85 18.20 0.429 0.304 0.169 Low ingredient and pig prices Feed cost/pig 7.54 7.99 8.22 8.42 8.85 9.03 0.203 < 0.001 0.673 Feed cost/lb gain 0.369 0.366 0.383 0.392 0.413 0.414 0.0019 < 0.001 0.339 Total revenue/pig 20.22 21.60 21.27 21.24 21.24 21.59 0.467 0.074 0.265 IOFC 12.68 13.61 13.05 12.82 12.38 12.56 0.300 0.048 0.181 A total of 300 pigs (DNA 600 × 241; initially 18.4 ± 0.50 kg BW) were used with 5 pigs per pen and 10 replications per treatment. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig—feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. Lysine requirement of grow-finish pigs 7 Dose–response curves for overall growth performance re- (Supplementary Figure S3A). The QP model resulted in the vealed that LMs were the best fit for ADG and G:F, with the best fit to optimize feed efficiency. The QP model equation SID Lys requirement to maximize ADG and G:F predicted was: G:F = −0.4830938 × (SID Lys, %) + 0.9555893 × (SID above 1.20% (Supplementary Figure S2A and S2B). At both Lys, %) – 0.027 with maximal G:F estimated at 0.99% SID high and low ingredient and pig prices, LMs resulted in the Lys (Supplementary Figure S3B). When modeling IOFC at high best fit for IOFC, with maximum IOFC estimated at <0.80% ingredient and pig prices, the BLL model resulted in the best SID Lys (Supplementary Figure S2C and S2D). fit, predicting no further improvement in IOFC past 0.76% SID Lys (Supplementary Figure S3C). Meanwhile, at low in- Experiment 3 gredient and pig prices, the LM and QP models had a compa- In 53 to 75  kg pigs, increasing SID Lys increased (linear, rable fit. The LM predicted maximum IOFC above 1.00% SID P < 0.001) final BW ( Table 8). Average daily gain increased Lys. The QP model equation was: IOFC = −14.5626 × (SID (linear, P < 0.001) with increasing SID Lys while for ADFI, Lys, %) + 26.6348 × (SID Lys, %) −0.085, with maximum there was a quadratic (P = 0.004) decrease with increasing IOFC estimated at 0.91% SID Lys. SID Lys. A linear and quadratic (P < 0.001) response was Experiment 4 observed for overall G:F with increasing SID Lys. Additionally, daily SID Lys intake and Lys intake per kg of gain increased In 76 to 100  kg pigs, increasing SID Lys did not signif- (linear and quadratic, P < 0.003) with increasing SID Lys. icantly affect (P > 0.10) final BW ( Table 9). Average daily For economic analysis, feed cost increased (linear and gain increased (linear, P = 0.022) with increasing SID Lys, quadratic, P < 0.023), while feed cost per kg of gain decreased while there was no observed difference (P > 0.10) in ADFI. (linear and quadratic, P < 0.012) with increasing SID Lys in As a result, increasing SID Lys numerically increased (quad- both economic scenarios. Meanwhile, at both high and low ratic, P < 0.10) G:F. with no improvement in G:F feeding ingredient and pig prices, increasing SID Lys increased line- beyond 0.86% SID Lys. Daily SID Lys intake and Lys intake arly (P < 0.002) revenue and IOFC. per kg of gain increased (linear, P < 0.001) with increasing Dose–response curves were evaluated for overall growth SID Lys. For economic analysis, feed cost increased (linear, performance with the LM being the best fitting model for P < 0.001), and feed cost per kg of gain increased (linear ADG, predicting maximum ADG above 1.00% SID Lys and quadratic, P < 0.041) with increasing SID Lys in both Table 7. Effects of increasing SID Lys on growth performance of pigs weighing 36 to 54 kg (experiment 2) SID Lys, % P Item 0.80 0.88 0.96 1.04 1.12 1.20 SEM Linear Quadratic BW, kg Initial 36.3 36.4 36.3 36.4 36.4 36.2 0.91 0.826 0.634 Final 53.9 54.0 54.2 54.3 54.2 54.4 0.93 0.316 0.806 ADG, kg 0.99 0.99 1.01 1.02 1.01 1.03 0.019 0.036 0.952 ADFI, kg 2.03 1.96 1.98 2.01 1.95 1.98 0.032 0.308 0.399 G:F 0.490 0.507 0.512 0.508 0.521 0.522 0.0108 <0.001 0.374 SID Lys g/d 16.20 17.24 18.98 20.89 21.83 23.82 0.336 <0.001 0.505 SID Lys g/kg gain 16.24 17.17 18.58 20.75 21.69 22.94 0.624 <0.001 0.963 Economics, $ High ingredient and pig prices Feed cost/pig 11.03 10.92 11.27 11.56 11.67 11.99 0.646 <0.001 0.357 Feed cost/kg gain 0.639 0.629 0.641 0.655 0.654 0.666 0.0141 0.002 0.424 Total revenue/pig 25.61 25.75 26.13 26.114 26.24 26.56 1.865 0.060 0.949 IOFC 14.58 14.83 14.86 14.58 14.57 14.57 1.235 0.669 0.624 Low ingredient and pig prices Feed cost/pig 6.73 6.75 7.01 7.32 7.42 7.71 0.406 <0.001 0.373 Feed cost/kg gain 0.390 0.389 0.398 0.415 0.416 0.429 0.0088 <0.001 0.464 Total revenue/pig 17.37 17.46 17.72 17.73 17.79 18.01 1.264 0.060 0.949 IOFC 10.64 10.71 10.71 10.41 10.37 10.29 0.876 0.097 0.659 A total of 608 pigs (600 × 241, DNA; initially 36.3 ± 0.91 kg BW) were used in 2 groups with 7 to 9 pigs per pen and 12 replications per treatment. A total of 285 pigs (initially 38.9 ± 0.81 kg BW) were fed trial diets for a 14-day period for group 1, and 323 pigs (initially 34.1 ± 0.95 kg BW) were fed trial diets for a 21-day period for group 2. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig—feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. 8 Royall et al. Table 8. Effects of increasing SID Lys lysine on growth performance of pigs weighing 53 to 75 kg (experiment 3) SID Lys, % P Item 0.65 0.72 0.79 0.86 0.92 1.00 SEM Linear Quadratic BW, kg d 0 53.1 53.2 53.2 53.2 53.1 53.2 0.86 0.926 0.857 d 21 72.9 73.4 74.1 74.2 74.7 75.7 1.03 <0.001 0.804 Overall (d 0 to 21) ADG, kg 0.94 0.96 1.00 1.01 1.03 1.06 0.017 <0.001 0.910 ADFI, kg 2.42 2.33 2.33 2.32 2.32 2.38 0.048 0.295 0.004 G:F 0.389 0.413 0.429 0.434 0.444 0.447 0.0050 <0.001 0.001 SID Lys g/d 15.79 16.78 18.37 19.97 21.56 23.94 0.396 <0.001 0.003 SID Lys g/kg gain 16.76 17.47 18.43 19.83 20.96 22.58 0.220 <0.001 0.002 Economics, $ High ingredient prices Feed cost/pig 15.04 15.23 15.07 15.53 15.57 16.45 0.344 <0.001 0.023 Feed cost/kg gain 0.760 0.733 0.720 0.727 0.721 0.738 0.0084 0.012 < 0.001 Total revenue/pig 28.89 30.31 30.54 31.20 31.53 32.59 0.568 <0.001 0.745 IOFC 13.85 15.07 15.47 15.68 15.96 16.14 0.327 <0.001 0.064 Low ingredient prices Feed cost/pig 8.64 8.78 8.83 9.23 9.34 10.05 0.203 <0.001 0.006 Feed cost/kg gain 0.437 0.422 0.422 0.432 0.432 0.451 0.0050 0.002 <0.001 Total revenue/pig 19.59 20.55 20.71 21.16 21.38 22.10 0.385 <0.001 0.745 IOFC 10.95 11.77 11.88 11.93 12.04 12.05 0.237 0.002 0.062 A total of 700 pigs (DNA 600 × 241; initial BW of 53.2 ± 0.86 kg) were used with 8 to 10 pigs per pen and 12 replications per treatment and were fed trial diets for a 21-d period in two groups. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig—feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. pricing scenarios. Increasing SID Lys tended to increase Experiment 5 (linear, P = 0.051) revenue at both high and low ingredient In 103- to 128-kg pigs, increasing SID Lys increased (linear, and pig prices. For IOFC, increasing SID Lys did not have a P = 0.025) final BW ( Table 10). Average daily gain increased significant effect ( P > 0.10) in either pricing scenario, how- linearly (P = 0.043) with increasing SID Lys, while there ever, pigs fed diets containing 0.65% or 0.72% SID Lys had was no observed difference (P > 0.10) in ADFI. As a result, the greatest numeric IOFC. increasing SID Lys increased (quadratic, P < 0.032) G:F, with When modeling dose–response curves for ADG, the pigs fed diets containing 0.71% SID Lys having the greatest BLL and LM models resulted in a comparable fit. The BLL numeric G:F. Daily SID Lys intake and Lys intake per kilo- model predicted no further improvement in ADG above gram of gain increased (linear, P < 0.001) with increasing SID 0.83% SID Lys, while the LM estimated maximum ADG Lys. above 1.00% (Supplementary Figure S4A). For G:F, the LM For economic analysis, at high ingredient and pig prices and QP models resulted in a comparable fit, with the LM there was no significant difference between treatments for predicting maximum G:F at greater that 1.00% SID Lys. feed cost per pig (P > 0.10). However, at low ingredient and The QP equation model was: G:F = -0.2244707 × (SID Lys, pig prices, increasing SID Lys increased (linear, P = 0.014) %) + 0.4156878 × (SID Lys, %) + 0.190, with 100% of max- feed cost per pig. At high prices, increasing SID Lys had a imum G:F estimated at 0.93% SID Lys (Supplementary Figure quadratic effect (P = 0.032) on feed cost per kg of gain. S4B). When modelling IOFC at high ingredient and pig prices, Meanwhile at low ingredient and pig prices, increasing SID the QP was the best fitting model. The QP model equation Lys increased (linear, P = 0.044) feed cost per kg of gain. In was: IOFC = -17.3293 × (SID Lys, %) + 27.0408 × (SID Lys, both economic scenarios, increasing SID Lys increased (linear, %) + 4.169, with maximum IOFC estimated at 0.78% SID P = 0.028) revenue. At high ingredient and pig prices, IOFC Lys (Supplementary Figure S4C). However, at low ingredient increased (linear and quadratic, P < 0.020) with increasing and pig prices, the BLL and LM models resulted in a compa- SID Lys. Additionally, increasing SID Lys had a quadratic ef- rable fit. The BLL model predicted a reduction in IOFC when fect (P = 0.004) on IOFC at low ingredient and pig prices, SID Lys increased past 0.76%, while the LM model estimated with pigs fed diets containing 0.71% SID Lys having the maximum IOFC at less than 0.58% SID Lys. greatest numeric IOFC in each scenario. Lysine requirement of grow-finish pigs 9 Table 9. Effects of increasing SID Lys on growth performance of pigs weighing 76 to 100 kg (experiment 4) SID Lys, % P Item 0.58 0.65 0.72 0.79 0.86 0.92 1.00 SEM Linear Quadratic BW, kg d 0 76.5 76.5 76.2 76.5 76.4 76.2 76.2 1.24 0.499 0.936 d 21 98.4 99.0 98.7 99.3 99.4 99.3 99.3 1.37 0.290 0.538 Overall (d 0 to 21) ADG, kg 1.04 1.06 1.07 1.09 1.09 1.10 1.10 0.026 0.022 0.488 ADFI, kg 2.94 2.92 2.89 2.88 2.86 2.89 2.88 0.067 0.357 0.423 G:F 0.355 0.365 0.371 0.378 0.383 0.380 0.382 0.0084 <0.001 0.097 SID Lys g/d 16.92 18.96 20.79 22.78 24.50 26.91 28.65 0.527 <0.001 0.874 SID Lys g/kg gain 16.30 17.82 19.43 20.96 22.52 24.54 26.15 0.472 <0.001 0.398 Economics, $ High ingredient and pig prices Feed cost/pig 17.91 18.29 18.53 18.69 18.94 19.42 19.91 0.470 <0.001 0.527 Feed cost/kg gain 0.824 0.810 0.815 0.819 0.826 0.844 0.864 0.0178 0.008 0.038 Total revenue/pig 31.79 32.98 33.29 33.28 33.51 33.65 33.84 0.836 0.051 0.405 IOFC 13.64 14.69 14.69 14.66 14.58 14.23 14.21 0.676 0.822 0.151 Low ingredient and pig prices Feed cost/pig 10.03 10.51 10.68 10.95 11.26 11.66 12.15 0.274 <0.001 0.486 Feed cost/kg gain 0.461 0.465 0.470 0.480 0.491 0.506 0.527 0.0105 <0.001 0.041 Total revenue/pig 21.55 22.36 22.57 22.57 22.73 22.82 22.95 0.567 0.051 0.405 IOFC 11.34 11.85 11.84 11.66 11.47 11.16 11.03 0.464 0.209 0.172 A total of 616 pigs (600 × 241, DNA; initially 76.4 ± 1.24 kg BW) were used in 2 groups with 8 to 10 pigs per pen and 6 replications for the 0.58% SID Lys treatment; 11 replications for the 0.65%, 0.72%, 0.79%, 0.86%, and 0.92% SID Lys treatments; and 5 replications for the 1.00% SID Lys treatment. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/ total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig—feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. When modelling dose response curves for ADG and G:F, Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0001558 × BW BLL models resulted in the best fit. The BLL model for max - − 0.04030769 × BW + 5.410 was developed. imum ADG predicted no further improvement past 0.64% SID Lys (Supplementary Figure S5A). Meanwhile, the BLL model for maximum G:F estimated no further improvement DISCUSSION above 0.59% SID Lys (Supplementary Figure S5B). When Essential AA requirements for growing-finishing pigs are modeling IOFC at high or low ingredient and pig prices, the commonly based on ratios to Lys. As a result, it is critical QP model resulted in the best fit. At high ingredient and pig to have an accurate estimation of Lys requirements to maxi- prices, the QP model equation was: IOFC = −42.6028 × (SID mize growth performance and optimize feed cost throughout Lys, %) + 54.9097 × (SID Lys, %) – 4.047, with max- the growing-finishing period ( Soto et al., 2019). Moreover, imum IOFC predicted at 0.64% SID Lys (Supplementary continuous advancements in modern pig genetics have led Figure S5C). Additionally, at low ingredient ant pig prices, to increased potential for growth performance and pro- the QP model equation was: IOFC = −25.9430 × (SID Lys, tein accretion, potentially leading to increased dietary nu- %) + 32.4160 × (SID Lys, %) + 0.901, with maximum IOFC trient requirements (O’Connell et al., 2006). Additionally, estimated at 0.62% SID Lys (Supplementary Figure S5D). advancements in dose–response models have provided a strategy to estimate nutrient requirements more accurately Prediction Equations (Gonçalves et al., 2016). This trend in genetic improvement, A summary of the optimum Lys:calorie ratio observed in each coupled with technological improvements to help optimize trial as well as the associated SID Lys intake per day and per health status, environmental conditions, and management kg of gain are provided in Table 11. These values were used to plans, has allowed for improvements in growth performance develop regression equations to predict the Lys:calorie ratio and carcass composition. Between 1980 and 2019, the av- required for maximum growth performance and IOFC of 18- erage market weight of pigs has increased by 18 kg (National to 128-kg pigs (Figure 1). To maximize growth performance, Pork Board, 2016, 2020). Coupled with this increased market the quadratic equation of Lys:calorie ratio, g of SID Lys/ weight, pigs have become more efficient. Between 1990 and Mcal of NE = 0.0002611 × BW – 0.0711037 × BW + 7.284 2019 average growth rate of wean-to-finish pigs increased was developed. To optimize IOFC, the quadratic equation of from 0.58 to 0.80  kg/day, while feed intake per kg of gain 10 Royall et al. Table 10. Effects of increasing SID Lys on growth performance of pigs weighing 103 to 128 kg (experiment 5) SID Lys, % P= Item 0.43 0.50 0.57 0.64 0.71 0.78 SEM Linear Quadratic BW, kg Initial 103.8 103.8 103.9 103.6 103.8 103.8 1.32 0.980 0.966 Final 125.9 127.3 127.0 127.6 128.4 127.3 1.14 0.025 0.102 ADG, kg 0.90 0.95 0.94 0.98 1.00 0.95 0.0256 0.043 0.108 ADFI, kg 3.01 3.01 2.90 2.96 2.98 2.89 0.049 0.102 0.956 G:F 0.300 0.315 0.325 0.329 0.334 0.331 0.064 <0.001 0.032 SID Lys, g/d 12.90 15.03 16.52 18.93 21.12 22.60 0.279 <0.001 0.408 SID Lys, g/kg gain 14.43 15.87 17.54 19.48 21.30 23.75 0.376 <0.001 0.178 Economics, $ High ingredient and pig prices Feed cost/pig 20.37 20.86 20.37 21.46 21.89 21.90 0.920 0.115 0.915 Feed cost/kg gain 0.927 0.898 0.884 0.894 0.895 0.922 0.0082 0.929 0.032 Total revenue/pig 32.01 33.84 33.56 34.96 35.62 34.54 1.07 0.028 0.229 IOFC 11.63 12.98 13.18 13.52 13.73 12.65 0.450 0.020 0.001 Low ingredient and pig prices Feed cost/pig 11.73 12.06 12.07 12.75 13.13 13.17 0.544 0.014 0.957 Feed cost/kg gain 0.534 0.519 0.524 0.531 0.537 0.555 0.0107 0.044 0.077 Total revenue/pig 21.70 22.95 22.75 23.71 24.15 23.42 0.724 0.028 0.229 IOFC 9.97 10.89 10.69 10.98 11.02 10.25 0.324 0.397 0.004 A total of 679 pigs (600 × 241, DNA; initial BW of 228.8 ± 2.9 lb) were used with 8 to 10 pigs per pen and 12 replications per treatment for the 0.43%, 0.50%, 0.57%, 0.71%, and 0.78% SID Lys treatments, 11 replications for the 0.64% SID Lys treatment, and were fed trial diets for a 21- or 28-d period in two groups. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/ total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig – feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. Table 11 Summary of the Lys:calorie ratio and associated SID Lys percentage and Lys intake that provided maximal response for growth performance and income over feed cost (IOFC) Trial BW range, kg Midpoint BW, kg Lys:calorie ratio, g of SID SID Lys, % SID Lys intake, g/d SID Lys g/kg of gain Lys/Mcal of NE Growth performance Trial 1 18 to 40 29 5.53 1.41 20.37 22.63 Trial 2 36 to 54 46 4.45 1.20 23.80 22.90 Trial 3 53 to 75 64 3.70 0.99 23.56 22.55 Trial 4 76 to 100 88 3.26 0.88 25.30 23.11 Trial 5 103 to 128 116 2.48 0.64 18.93 19.48 IOFC Trial 1 18 to 40 29 4.39 1.12 16.46 18.46 Trial 2 36 to 54 46 3.56 0.96 19.00 18.60 Trial 3 53 to 75 64 3.37 0.91 21.11 20.20 Trial 4 76 to 100 88 2.89 0.78 22.50 20.84 Trial 5 103 to 128 116 2.48 0.64 18.93 19.48 Five trials were conducted to determine maximum SID Lys,% in grow-finish pigs (600 × 241, DNA). Income over feed cost = total revenue/pig—feed cost/pig. decreased from 3.2 to 2.6  kg during that same time frame Estimations of dietary Lys requirements for growing- (National Pork Board, 2020; PigChamp, 1990). Similarly, this finishing pigs have changed considerably in the last 30 years. improved growth performance was observed in our study, as Cromwell et al. (1993) suggested that the total Lys require- pigs grew at an average between 0.89 and 1.08 kg/day across ment for barrows and gilts from 35 to 105 kg was 0.60% and our 5 experiments. 0.90%, respectively. Hahn et al. (1995) suggested a total Lys Lysine requirement of grow-finish pigs 11 requirement for barrows and gilts weighing between 90 and performance when they weigh less than 100 kg. However, in 110 kg of 0.49% and 0.52%, respectively. More recently, in late-finishing pigs (103 to 128 kg), maximum economic per - a meta-analysis with PIC (Hendersonville, TN) genetic lines, formance is achieved at similar levels as maximum growth Gonçalves et al. (2017) suggested that the SID Lys require- performance. ment for barrows and gilts in predominantly Pietrain-sired In conclusion, the SID Lys estimate for maximum IOFC and pigs was 1.11% and 1.16% (25 to 50 kg), 0.91% and 0.94% growth performance was determined for 5 different weight (50 to 75 kg), 0.78% and 0.80% (75 to 100 kg), and 0.70% ranges from 18 to 128 kg. In addition, prediction equations and 0.75% (100 to 135  kg), respectively. Soto et al. (2019) were developed to describe the Lys:calorie ratio that best observed that late finishing pigs (102 to 128 kg) grown in the met biological requirements for growth performance and same facilities with similar genetic maternal and paternal lines optimized IOFC. Therefore, this data can be used to formu- as our study achieved maximum ADG and G:F at 0.62% and late SID Lys diet levels for Duroc-sired pigs ranging in weight 0.63% SID Lys, respectively. In our study, the SID Lys estimate from 18 to 128 kg. for maximum growth performance was 1.41% to 1.50%, at least 1.20%, 0.99% to 1.00%, 0.83% to 0.93%, and 0.59% SUPPLEMENTARY DATA to 0.64% for pigs weighing 18 to 40 kg, 36 to 54 kg, 53 to 75 kg, 76 to 100 kg, and 103 to 128 kg, respectively. Supplementary data are available at Translational Animal During the grower period (25 to 50 kg) we observed con- Science online. siderably higher estimates than those of Gonçalves et al. Supplementary Figure S1. Estimation of standardized ileal (2017). This difference may be a result of drastic differences digestible (SID) lysine requirement to maximize ADG, G:F, in daily feed intake (2.31  kg/day in Gonçalves vs. 1.99  kg/ and income over feed cost (IOFC) for 18 to 40 kg Duroc-sired day in current study). Pigs in our study may have required pigs (600 × 241, DNA; Exp. 1). A total of 300 pigs (600 × 241, a considerably higher SID Lys percentage in the diet to DNA; initially 18.4 ± 0.50  kg) were used in a 24-d growth meet a similar Lys intake per kg of gain. Similarly, in pigs trial with 5 pigs per pen and 10 replications per treatment. weighing between 50 and 100 kg, we observed higher lysine Barrows and gilts were penned together with gender equalized requirements than those of Gonçalves et al. (2017). In late by block. A. The linear model (LM) and quadratic polynomial finishing (103 to 128 kg pigs), we observed a similar SID Lys (QP) models had a comparable fit (BIC = -184.9 and -182.9, requirement to those of Soto et al. (2019), which was consid- LM and QP, respectively) with the SID Lys requirement to erably lower than those of Gonçalves et al. (2017). Variation achieve maximal ADG predicted above 1.50% with LM and in Lys requirements among studies could be attributable to 1.41% with the QP model. The QP model equation was: differences in genetic capability for protein deposition, amino ADG = -0.282148 × (SID Lys, %) + 0.797053 × (SID Lys, acid digestibility, or immune stress (Kendall et al., 2007). %) + 0.339. B. The LM had the best fit with the SID Lys re - The present studies were conducted under a controlled, high- quirement to achieve maximal feed efficiency predicted above health research environment. Thus, Lys requirement estimates 1.50% C. The LM was the best fitting model with the SID Lys might change with different environmental conditions. requirement to achieve maximal IOFC with high ingredient Lysine requirements are often expressed as a function of and pig prices predicted at less than 1.00% SID Lys. D. The SID Lys required per kg of BW gain. Our estimated require- LM and BLL models had a comparable fit (BIC = 178.0 and ment ranged from approximately 22.6 to 23.3 g SID Lys/kg 179.4, LM and BLL, respectively) with the SID Lys require- gain for 18 to 75 kg pigs and from 21.3 to 22.5 g SID Lys/ ment to achieve maximal IOFC with low ingredient and pig kg gain for 76 to 128 kg pigs. In comparison, Shelton et al. prices predicted at less than 1.00% with the LM, and 1.12% (2011) and Main et al. (2008) observed a requirement ranging with the BLL model. The BLL model predicted a reduction in between 19.6 and 23.0  g SID Lys/kg gain in pigs weighing IOFC when SID Lys increased past 1.12% SID Lys. 35 to 110  kg. Additionally, Main et al. (2008) and Soto et Supplemental Figure S2. Estimation of standardized ileal al. (2019) observed a requirement ranging between 17.0 and digestible (SID) lysine requirement to maximize ADG, G:F, 22.6 g SID Lys/kg gain in pigs weighing 100 to 130 kg. The and income over feed cost (IOFC) for 36 to 54  kg Duroc- increased requirement of SID Lys intake per kg of BW gain sired pigs (600 × 241, DNA; Exp. 2). A total of 608 pigs observed in our trials may be a result of pigs depositing a (600 × 241, DNA; initially 36.3 ± 0.91  kg BW) were used higher proportion of protein rather than lipids compared to with in a pair of 14 or 21-d growth trials, with 7 to 9 pigs previous research. per pen and 12 replications per treatment. Barrows and gilts Economic analysis, as well as growth performance, is were penned together with gender equalized by block. A. The vital when developing nutritional programs. Income over linear model (LM) was the best fitting model with the SID Lys feed cost accounts for the gross sale revenue and feed ex- requirement to achieve maximal ADG predicted at greater pense generated. Multiple studies have observed that nutrient than 1.20% SID Lys. B. The LM was the best fitting model requirements to maximize biological performance may align with the SID Lys requirement to achieve maximal feed effi - with optimal IOFC estimates (De La Llata et al., 2001; Main ciency predicted at greater than 1.20% SID Lys. C. The LM et al., 2008). In contrast, our results in experiments 1, 2, 3, was the best fitting model with the SID Lys requirement to and 4 (18 to 100 kg pigs) suggest that the SID Lys require- achieve maximal IOFC with high ingredient and pig prices ment to optimize IOFC is considerably lower than the biolog- predicted at less than 0.80% SID Lys. D. The LM was the best ical requirement for maximal growth performance. However, fitting model with the SID Lys requirement to achieve maxi - in experiment 5, the SID Lys requirement for maximum IOFC mal IOFC with low ingredient and pig prices predicted at less and growth performance were more closely aligned (0.59% than 0.80% SID Lys. to 0.64%). These results would suggest that, in the economic Supplemental Figure S3. Estimation of standardized ileal scenarios considered in our analysis, there is no economic digestible (SID) lysine requirement to maximize ADG, G:F, advantage to feed pigs to their maximum biological growth and income over feed cost (IOFC) for 53 to 75 kg Duroc-sired 12 Royall et al. pigs (600 × 241, DNA; Exp. 3). A total of 700 pigs (DNA Lys treatment. Barrows and gilts were penned together with 600 × 241; initial BW of 53.2 ± 0.86  kg) were used in two gender equalized by block. A. The broken line linear (BLL) was separate 21-d growth trials, with 8 to 10 pigs per pen and the best fitting model with the SID Lys requirement to achieve 12 replications per treatment. Barrows and gilts were penned maximal ADG predicted at 0.64%. The BLL predicted no fur- together with gender equalized by block. A. The linear model ther improvement in ADG past 0.64% SID Lys. B. The BLL (LM) was the best fitting model with the SID Lys require - was the best fitting model with the SID Lys requirement to a - ment to achieve maximal ADG predicted above 1.00% SID chieve maximal feed efficiency predicted at 0.59%. The BLL Lys. B. The quadratic polynomial (QP) was the best fitting predicted no further improvement in feed efficiency past 0.59% model with the SID Lys requirement to achieve maximal feed SID Lys. C. The quadratic polynomial (QP) was the best fitting efficiency predicted at 0.99%. The QP model equation was: model with the SID Lys requirement to achieve maximal IOFC G:F = -0.4830938 × (SID Lys, %) + 0.9555893 × (SID Lys, at high ingredient and pig prices predicted at 0.64% SID Lys. %) – 0.027. C. The broken line linear (BLL) was the best The QP model equation was: IOFC = -42.60278 × (SID Lys, fitting model with the SID Lys requirement to achieve max - %) + 54.9097 × (SID Lys, %) – 4.047. D. The QP was the best imal IOFC with high ingredient and pig prices predicted at fitting model with the SID Lys requirement to achieve maximal 0.76%. The BLL predicted no further improvement in IOFC IOFC at low ingredient and pig prices predicted at 0.62% SID past 0.76% SID Lys. D. The LM and QP models had a com- Lys. The QP model equation was: IOFC = -25.9430 × (SID Lys, parable fit (BIC = 191.8 and 192.4, LM and QP, respectively) %) + 32.4160 × (SID Lys, %) + 0.901. with the SID Lys requirement to achieve maximal IOFC with low ingredient and pig prices predicted above 1.00% with the LM, and 0.91% with the QP. The QP model equation ACKNOWLEDGMENTS was: IOFC = -14.5626 × (SID Lys, %) + 26.6348 × (SID Lys, Contribution no. 22-102-J of the Kansas Agricultural %) - 0.085. Experiment Station, Manhattan, KS USA 66506-0201. Supplemental Figure S4. Estimation of standardized ileal digestible (SID) lysine requirement to maximize ADG, G:F, and income over feed cost (IOFC) for 76 to 100 kg Duroc- CONFLICT OF INTEREST STATEMENT sired pigs (600 × 241, DNA; Exp. 4). A total of 616 pigs The authors declare no conflict of interest. (600 × 241, DNA; initially 76.4 ± 1.24  kg BW) were used in two separate 21-d growth trials, with 8 to 10 pigs per pen and 6 replications for the 0.58% SID Lys treatment; 11 LITERATURE CITED replications for the 0.65, 0.72, 0.79, 0.86, and 0.92% SID Lys treatments; and 5 replications for the 1.00% SID Lys treat- AOAC International. 2012. Official methods of analysis of AOAC In - ternational. 19th ed. Gaithersburg, MD: Association of Official An - ment. Barrows and gilts were penned together with gender alytical Chemists. equalized by block. A. The broken line linear (BLL) and lin- Campbell, R. G., M. R. Taverner. 1988. Genotype and sex effects on the ear model (LM) models had a comparable fit (BIC = -179.4 relationship between energy intake and protein deposition in grow- and -179.1, BLL and LM, respectively) with the SID Lys re- ing pigs. J. Anim. Sci. 66:676–86. doi:10.2527/jas1988.663676x quirement to achieve maximal ADG predicted at 0.83% with Cemin, Henrique S., Hayden E. Williams, Mike D. Tokach, Steve the BLL, and greater than 1.00% with the LM model. The S. Dritz, Jason C. Woodworth, Joel M. DeRouchey, Robert D. BLL predicted no further improvement in ADG past 0.83% Goodband, Kyle F. Coble, Brittany A. Carrender, and Mandy J. SID Lys. B. The LM and quadratic polynomial (QP) models Gerhart. 2020. Estimate of the energy value of soybean meal rela- had a comparable fit (BIC = -330.1 and -331.0, LM and QP, tive to corn based on growth performance of nursery pigs. J. Anim. respectively) with the SID Lys requirement to achieve maxi- Sci. Biotech. 11:70–79 https://jasbsci.biomedcentral.com/track/ pdf/10.1186/s40104-020-00474-x mal feed efficiency predicted at greater than 1.00% with the Cromwell, G. L., T. R. Cline, J. D. Crenshaw, T. D. Crenshaw, R. C. LM, and 0.93% with the QP model. The QP equation model 2 Ewan, C. R. Hamilton, A. J. Lewis, D. C. Mahan, E. R. Miller, and J. was: G:F = -0.2244707 × (SID Lys, %) + 0.4156878 × (SID E. Pettigrew. 1993. The dietary protein and (or) lysine requirements Lys, %) + 0.190. C. The QP was the best fitting model with of barrows and gilts. NCR-42 committee on swine nutrition. J. the SID Lys requirement to achieve maximal IOFC at high Anim. Sci. 74:93–102. doi:10.2527/1993.7161510x ingredient and pig prices predicted at 0.78% SID Lys. The De La Llata, M., S. S. Dritz, M. R. Langemeier, M. D. Tokach, R. D. QP model equation was: IOFC = -17.3293 × (SID Lys, Goodband, and J. L. Nelssen. 2001. Economics of increasing %) + 27.0408 × (SID Lys, %) + 4.169. D. The BLL and LM lysine:calorie ratio and adding dietary fat for growing-finishing models had a comparable fit (BIC = 202.5 and 202.6, BLL pigs reared in a commercial environment. Swine Health Prod. and LM, respectively) with the SID Lys requirement to achieve 9:215–223. Gonçalves, M. A., N. M. Bello, S. S. Dritz, M. D. Tokach, J. M. maximal IOFC at low ingredient ant pig prices predicted DeRouchey, J. C. Woodworth, and R. D. Goodband. 2016. An at 0.76% with the BLL, and less than 0.58% with the LM update on modeling dose-response relationships: accounting for model. The BLL model predicted a reduction in IOFC when correlated data structure and heterogeneous error variance in SID Lys increased past 0.76% SID Lys. linear and nonlinear mixed models. J. Anim. Sci. 94:1940–1950. Supplemental Figure S5. Estimation of standardized ileal di- doi:10.2527/jas.2015-0106 gestible (SID) lysine requirement to maximize ADG, G:F, and Gonçalves, M. A. D., U. Orlando, W. Cast, and M. Culberson. 2017. income over feed cost (IOFC) for 103 to 128 kg Duroc-sired Standardized ileal digestible lysine requirements for finishing PIC pigs (600 × 241, DNA; Exp. 5). A total of 679 pigs (600 × 241, pigs under commercial conditions: A meta-analysis. J. Anim. Sci. DNA; initial BW of 228.8 ± 2.9 lb) were used in two separate 95(E. Suppl. 2):E131–3132. 21- or 28-d growth trials, with 8 to 10 pigs per pen and 12 Hahn, J. D., R. R. Biehl, and D. H. Baker. 1995. Ideal digestible lysine level for early- and late-finishing swine. J. Anim. Sci. 73:773–84. replications per treatment for the 0.43, 0.50, 0.57, 0.71 and doi:10.2527/1995.733773x 0.78% SID Lys treatments, 11 replications for the 0.64% SID Lysine requirement of grow-finish pigs 13 Kendall, D. C., A. M. Gaines, B. J. Kerr, and G. L. Allee. 2007. True growing-finishing pigs. Livest. Sci. 101:1690179. doi:10.1016/j. ileal digestible tryptophan to lysine ratios in ninety- to one hun- livprodsci.2005.11.024 dred twenty-five-kilogram barrows. J. Anim. Sci. 73:3000–3008. PigChamp. 1990. Grow-finish production values . Webster City, IA: doi:10.2527/jas.2007-0013 Swine Graphics. Main, R. G., S. S. Dritz, M. D. Tokach, R. D. Goodband, and J. L. Shelton, N. W., M. D. Tokach, S. S. Dritz, R. D. Goodband, J. L. Nelssen. 2008. Determining an optimum lysine:calorie ratio for Nelssen, and J. M. DeRouchey. 2011. Effects of increasing dietary barrows and gilts in a commercial finishing facility. J. Anim. Sci. standardized ileal digestible lysine for gilts grown in a commer- 86:2190–207. doi:10.2527/jas.2007-0408 cial finishing environment. J. Anim. Sci. 89:3587–95. doi:10.2527/ National Pork Board. 2016. Quick facts. Des Moines, IA: National jas.2010-3030 Pork Board. – [accessed August 2, 2021]. Retrieved from: https:// Soto, J. A., M. D. Tokach, S. S. Dritz, J. C. Woodworth, J. M. DeRouchey, porkgateway.org/wp-content/uploads/2015/07/quick-facts-book1. R. D. Goodband, and F. Wu. 2019. Optimal dietary standardized pdf. ileal digestible lysine and crude protein concentration for growth National Pork Board. 2020. Production Analysis Summary for U.S. and carcass performance in finishing pigs weighing greater than Pork Industry: 2017-2019. Des Moines, IA: National Pork Board. – 100 kg. J. Anim. Sci. 97:1701–1711. doi:10.1093/jas/skz052 [accessed August 2, 2021]. Retrieved from: https://library.pork.org/ Suzuki, K., T. Shibata, H. Kadowaki, H. Abe, and T. Toyoshima. 2003. media/?mediaId=4D0CDE8D-9898-44F4-A2FB321F87DE331D. Meat quality comparison of Berkshire, Duroc, and crossbred pigs NRC. 2012. Nutrient requirements of swine. 11th revised edn. National by Berkshire and Duroc. Meat Sci. 64:35–42. doi:10.1016/s0309- Academic Press, Washington, DC. 1740(02)00134-1 O’Connell, M. K., P. B. Lynch, and J. O’Doherty. 2006. The effect of Yen, J. T., J. Klindt, B. J. Kerr, F. C. Buonomo. 2005. Lysine require- dietary lysine restriction during the grower phase and subsequent ment of finishing pigs administered porcine somatotropin by dietary lysine concentration during the realimentation phase on sustained-release implant. J. Anim. Sci. 83:2789–97. the performance, carcass characteristics and nitrogen balance of doi:10.2527/2005.83122789x http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Translational Animal Science Oxford University Press

Effects of standardized ileal digestible lysine level on growth performance and economic return for 18 to 128 kg Duroc-sired pigs

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Translational Animal Science, 2022, 6, 1–13 https://doi.org/10.1093/tas/txac103 Advance access publication 12 August 2022 Non Ruminant Nutrition Effects of standardized ileal digestible lysine level on growth performance and economic return for 18 to 128 kg Duroc-sired pigs † †,1 † Rafe Q. Royall, Robert D. Goodband, Mike D. Tokach, † †, ‡ Joel M. DeRouchey, Jason C. Woodworth, and Jordan T. Gebhardt Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS 66506-0201, USA Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506-0201, USA Corresponding author: goodband@ksu.edu ABSTRACT The recent shift of the U.S. swine industry toward improved pork quality, such as color, marbling, and firmness, has led to increased use of Duroc-sired pigs in the marketplace. Our objective was to determine the standardized ileal digestible (SID) Lys requirement estimates for Duroc- sired (600 × 241, DNA, Columbus, NE) pigs from 18 to 128 kg BW. We conducted a series of experiments using corn–soybean meal-based diets with pigs allotted to 6 or 7 treatments in randomized complete block designs. In all experiments an equal number of barrows and gilts were used within a pen. In experiment 1, 300 pigs (initially 18.4 ± 0.50 kg) were used with 5 pigs per pen and 10 pens per treatment with 6 SID Lys levels from 1.00% to 1.50%. Increasing SID Lys increased (linear, P < 0.040) final BW, ADG, G:F, and Lys intake/kg of gain, and decreased (linear, P = 0.012) ADFI. In experiment 2, 608 pigs (initially 36.3 ± 0.91 kg) were used with 7 to 9 pigs per pen and 12 pens per treatment with 6 SID Lys levels from 0.80% to 1.20%. Increasing SID Lys increased (linear, P ≤ 0.036) ADG, G:F , and Lys intake/kg of gain. In experiment 3, 700 pigs (initially 53.2 ± 0.86 kg) were used with 8 to 10 pigs per pen and 12 pens per treatment with 6 SID Lys levels from 0.65% to 1.00%. Increasing SID Lys increased (linear, P < 0.001) final BW, ADG, and Lys intake/kg of gain, decreased (quadratic, P = 0.004) ADFI, and improved (quadratic, P < 0.001) G:F. In experiment 4, 616 pigs (initially 76.4 ± 1.25 kg) were used with 8 to 10 pigs per pen and 5, 6, or 11 pens per treatment with 7 SID Lys levels from 0.58% to 1.00%. Increasing SID Lys increased (linear, P ≤ 0.022) ADG, Lys intake per kilogram of gain, and G:F. In experiment 5, 679 pigs (initially 103.8 ± 1.32 kg) were used with 8 to 10 pigs per pen and 11 or 12 pens per treatment with 6 SID Lys levels from 0.43% to 0.78%. Increasing SID Lys increased (linear, P ≤ 0.043) final BW, ADG, and Lys intake per kilogram of gain, and improved (quadratic, P ≤ 0.032) G:F. Using results from all experiments, the quadratic equation of Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0002611 × BW – 0.0711037 × BW + 7.284 was developed to reflect the requirement for maximal growth performance from 18 to 128 kg BW. Maximal income over feed cost (IOFC) is best described by the quadratic equation: Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0001558 × BW − 0.04030769 × BW + 5.410. These data provide updated SID Lys estimates for Duroc-sired grow-finish pigs. LAY SUMMARY Lysine is typically the first limiting amino acid in corn–soybean meal-based swine diets, and as such, having an accurate estimate of lysine requirements for various genotypes is vitally important to optimize both growth performance and economic return. The focus of this research was to determine the standardized ileal digestible (SID) lysine requirement estimates of Duroc-sired pigs throughout the growing-finishing period. A series of five experiments were conducted where pigs were fed increasing levels of SID lysine at various weight ranges between 18 and 128 kg. Using the results of each individual experiment, we were able to develop equations to predict the Lys:calorie ratio required to maximize both growth performance and economic return. These equations can be utilized by swine production systems to optimize feeding programs for this genotype of pigs. Key words: amino acid, economics, growth, grow-finish pig, lysine Abbreviations: ADFI, average daily feed intake; ADG, average daily gain; BW, body weight; CP, crude protein; DM, dry matter; G:F, gain-to-feed; RCBD, randomized complete block design; SID, standardized ileal digestibility; STTD, standard total tract digestibility INTRODUCTION estimation of Lys requirements is crucial to maximize lean growth while optimizing feed cost in growing-finishing pigs. Improvements in modern swine genetics have resulted in Numerous factors have an impact on Lys requirements, such an increased potential for growth performance and pro- as genetics, environmental conditions, sex, and pig body tein accretion, which may cause a shift in dietary nutrient weight (Campbell and Taverner, 1988). Genetic suppliers requirements. As a result, it is important to continuously ana- provide estimates for amino acid requirements; however, lyze and reassess dietary nutrient requirements (O’Connell et validating these levels is necessary to optimize growth per- al., 2006). Lysine is typically the first limiting amino acid in formance and economic returns (De La Llata et al., 2001; corn–soybean meal-based swine diets, and as such an accurate Received May 6, 2022 Accepted July 21, 2022. Published by Oxford University Press for the American Society of Animal Science 2022. This work is written by (a) US Government employee(s) and is in the public domain in the US. 2 Royall et al. Main et al., 2008; Shelton et al., 2011). Additionally, it is im- increased within the industry by increasing both soybean portant to have an appreciation for the biological and eco- mean and L-Lys HCl. Previous research by Yen et al. (2005) nomic implications of feeding below, at, or above biological and Main et al. (2008), and many others have employed a sim- requirements throughout the grower-finishing period when ilar diet formulation strategy in determining Lys requirements developing feeding regimens (Main et al., 2008). of finishing pigs. In all experiments, pens of pigs were weighed, Recently, the U.S. swine industry has shifted toward an and feed disappearance was recorded approximately every 7 d emphasis for improved pork quality (color, marbling, and to determine ADG, ADFI, and G:F in all experiments. firmness), which has led to increased usage of Duroc-sired Experiment 1 pigs in the marketplace. Suzuki et al. (2003) observed that Duroc-sired pigs had excellent growth rates and intramus- A total of 300 pigs (initially 18.4 ± 0.50 kg to approximately cular fat content. Moreover, Soto et al. (2019) observed that 40 kg) were used in a 24-d study. There were 5 mixed-gender Duroc-sired late finishing pigs had 6% greater overall feed pigs per pen at a floor space of 0.30 m per pig. Pens of pigs intake compared with Pietrain-influence sired pigs reported were allotted by BW and randomly assigned to 1 of 6 dietary by Gonçalves et al. (2017). Therefore, the objective of these treatments with 10 replications per treatment in a randomized experiments was to determine the standardized ileal digestible complete block design (RCBD). Dietary treatments were (SID) Lys estimates for Duroc-sired finishing pigs from 18 to corn–soybean meal based and formulated to 1.00%, 1.10%, 128 kg with the intent of developing an SID Lys requirement 1.20%, 1.30%, 1.40%, or 1.50% SID Lys containing 0.25%, estimate curve for this genotype. 0.30%, 0.35%, 0.40%, 0.45%, and 0.50% L-Lys HCl, re- spectively, with other feed-grade AAs added as necessary to maintain ratios relative to Lys (Table 1). MATERIALS AND METHODS Experiment 2 General A total of 608 pigs (initially 36.3 ± 0.91 kg to approximately The Kansas State University Institutional Animal Care and Use 54 kg) were used in two consecutive groups of approximately Committee approved the protocol used in these experiments. 300 pigs with the group 1 study lasting 14-d and group 2 All experiments were conducted at the Kansas State University lasting 21 d. There were 7 to 9 mixed gender pigs per pen at a Swine Teaching and Research Center in Manhattan, KS. The floor space of 0.74 m per pig. Pigs were allotted by BW and facilities were totally enclosed and environmentally regulated. randomly assigned to 1 of 6 dietary treatments in an RCBD. In experiment 1, each pen (1.21 × 1.21-m) was equipped with a The dietary treatments included 6 SID Lys concentrations 4-hole, dry self-feeder, and a nipple waterer. Pens were located (0.80%, 0.88%, 0.96%, 1.04%, 1.12%, and 1.20%), with over a metal tri-bar floor with a 1.21-m pit underneath for 12 replications per treatment. manure storage. In experiments 2, 3, 4, and 5, each pen was equipped with a 2-hole dry, single-sided feeder (Farmweld, Experiment 3 Teutopolis, IL) and a 1-cup waterer, and adjustable gates to A total of 700 pigs (initially 53.2 ± 0.86 kg to approximately allow 0.74 m per pig. Pens were located over a completely 75 kg) were used in two consecutive groups of approximately slatted concrete floor with a 1.21-m pit underneath for ma - 350 pigs. Each study lasted 21 d. There were 8 to 10 pigs per nure storage. A robotic feeding system (FeedPro; Feedlogic pen with similar numbers of barrows and gilts in each pen. Corp., Wimar, MN) was used to deliver and record daily feed Pens of pigs were allotted by BW and randomly assigned to additions to each individual pen. Pigs were provided ad lib- 1 of 6 dietary treatments in a RCBD. The dietary treatments itum access to water and feed in meal form throughout the included 6 SID Lys concentrations (0.65%, 0.72%, 0.79%, experiments. Complete diets were manufactured at Hubbard 0.86%, 0.93%, and 1.00%), with 12 replications per Feeds, Beloit, KS for each experiment. All experimental diets treatment. were corn–soybean meal based. Ingredient nutrient composi- tion and SID AA coefficients were derived from NRC (2012), Experiment 4 except for NE of soybean meal which was set at 100% that A total of 616 pigs (initially 76.4 ± 1.25 kg to approximately of corn (Cemin et al., 2020). In experiment 1, six individual 106 kg) were used in two consecutive groups of approximately diets were manufactured (Table 1). In experiments 2, 3, 4, and 300 pigs. Each study lasted 21 d. There were 8 to 10 mixed 5, two diets were formulated to 0.80 and 1.20, 0.65 and 1.00, gender pigs per pen with similar numbers of barrows and gilts 0.58 and 1.00, and 0.43% and 0.78% SID Lys, respectively. placed in each pen. Pens of pigs were allotted by BW and ran- These dietary treatments were blended via a robotic feeding domly assigned to 1 of 7 dietary treatments in a RCBD. The system to establish the range of SID Lys levels in each experi- dietary treatments included 7 SID Lys concentrations (0.58%, ment (Tables 2 and 3). 0.65%, 0. 72%, 0.79%, 0.86%, 0.92%, and 1.00%), with 11 In each experiment, Duroc-sired pigs (600 × 241, DNA, replications for the 0.65%, 0.72%, 0.79%, 0.86%, and 0.92% Columbus NE) were used to estimate the SID Lys requirement. SID Lys treatments; 6 replications for the 0.58% SID Lys treat- Barrows and gilts were penned together with gender equalized ment; and 5 replications for the 1.00% SID Lys treatment. by pen or block for each experiment. For all experiments, ratios of other AAs to Lys were maintained well above re- Experiment 5 quirement estimates to ensure that Lys was the first-limiting A total of 679 pigs (initially 103.8 ± 1.32  kg to approxi- AA. Although the increase in dietary Lys was brought about mately 128 kg) were used in two consecutive groups of ap- by increasing the ratio of soybean meal to corn which also proximately 330 pigs. Each study lasted 21 and 28 d. There increased the CP content of the diet, Lys was the first limiting were 8 to 10 mixed gender pigs per pen with similar num- AA. This formulation strategy was used to make the results bers of barrows and gilts placed in each pen. Pens of pigs more translational to application, as SID Lys is typically were allotted by BW and randomly assigned to 1 of 6 dietary Lysine requirement of grow-finish pigs 3 Table 1. Diet composition in experiment 1 (as-fed basis) SID Lys, % Item 1.00 1.10 1.20 1.30 1.40 1.50 Ingredient, % Corn 69.40 66.55 63.67 60.81 57.93 55.13 Soybean meal, 46.5% CP 25.61 28.11 30.61 33.11 35.61 38.11 Corn oil 2.00 2.25 2.50 2.75 3.00 3.20 Limestone 1.00 1.00 0.98 0.98 0.95 0.95 Monocalcium P, 21% P 0.70 0.65 0.65 0.60 0.60 0.55 Sodium chloride 0.50 0.50 0.50 0.50 0.50 0.50 L-Lys-HCl 0.25 0.30 0.35 0.40 0.45 0.50 DL-Met 0.07 0.11 0.15 0.19 0.23 0.26 L-Thr 0.08 0.11 0.14 0.17 0.20 0.23 L-Trp 0.01 0.01 0.02 0.02 0.03 0.03 L-Val 0.00 0.02 0.05 0.08 0.11 0.15 Vitamin premix with phytase 0.25 0.25 0.25 0.25 0.25 0.25 Trace mineral premix 0.15 0.15 0.15 0.15 0.15 0.15 Total 100 100 100 100 100 100 Calculated analysis SID AA, % Lys, % 1.00 1.10 1.20 1.30 1.40 1.50 Ile:Lys 65 63 61 59 58 57 Leu:Lys 140 132 126 120 116 112 Met:Lys 32 34 35 36 37 37 Met and Cys:Lys 58 58 58 58 58 58 Thr:Lys 63 63 63 63 63 63 Trp:Lys 19.2 19.1 19.1 19.1 19.0 19.0 Val:Lys 71 70 70 70 70 70 His:Lys 43 41 40 39 38 37 Total Lys, % 1.13 1.23 1.34 1.45 1.55 1.65 NE, kcal/kg 2,553 2,553 2,553 2,553 2,553 2,553 SID Lys:NE, g/Mcal 3.92 4.31 4.70 5.09 5.48 5.88 SID Lys:CP, % 5.47 5.69 5.88 6.05 6.20 6.34 CP, % 18.3 19.3 20.4 21.5 22.6 23.7 Ca, % 0.68 0.68 0.68 0.68 0.68 0.68 P, % 0.51 0.51 0.52 0.52 0.53 0.53 STTD P, % 0.40 0.40 0.40 0.40 0.40 0.40 Diets were fed from 18.4 to 40.2 kg BW. Ronozyme Hiphos (GT) 2700 (DSM Nutritional Products, Inc, Parsippany NJ), provided 1248 phytase units (FYT/kg), for an estimated release of 0.12% STTD P. Provided per kilogram of premix: 1,653,465 IU Vitamin A, 661,386 IU Vitamin D , 17,637 IU Vitamin E, 1323 mg Vitamin K, 13 mg Vitamin B , 3 12 19,842 mg niacin, 11,023 mg pantothenic acid, 3,306 mg menadione. Provided per kilogram of premix: 11 g Cu, 0.2 g I, 73 g Fe, 22 g Mn, 0.2 g of Se, 73 g Zn. Ingrdient values and SID coefficients were derived from NRC (2012). treatments in a RCBD. The dietary treatments included 6 SID beginning of each trial. Diet samples were stored at −20 °C Lys concentrations (0.43%, 0.50%, 0.57%, 0.64%, 0.71%, until they were homogenized, subsampled, and submitted for and 0.78%), with 12 replications for the 0.43%, 0.50%, analysis of AA profile (method 994.12; AOAC International, 0.57%, 0.71%, and 0.78% SID Lys treatments, and 11 2012) conducted by Ajinomoto Animal Nutrition North replications for the 0.64% SID Lys treatment. America, Inc. (Eddyville, IA). Results of laboratory analysis indicated total nutrient profiles were consistent with expected diet formulation values. Chemical Analysis A sample of each diet in experiment 1 and from the lowest Economic Analysis and highest SID Lys, % diets in experiments 2, 3, 4, and 5 was submitted for AA profile ( Tables 4 and 5). In experi- For the economic analysis, feed cost/pig, feed cost/kg gain, ment 1, representative diet samples were obtained from every revenue per pig, and IOFC were calculated for high- and third bag of feed. In experiments 2, 3, 4, and 5, diet samples low-priced diets. High-priced diet costs were determined were taken from 6 feeders per dietary treatment 3 d after the using the following ingredient prices: corn = $6.00/bushel 4 Royall et al. Table 2. Diet composition experiment 2 and 3 (as-fed basis) Table 3. Diet composition experiment 4 and 5 (as-fed basis) experiment 2 experiment 3 experiment 4 experiment 5 1 2 1 2 SID Lys, % SID Lys, % SID Lys, % SID Lys, % Item 0.80 1.20 0.65 1.00 Item 0.58 1.00 0.43 0.78 Ingredient, % Ingredient, % Corn 78.62 64.75 83.12 71.87 Corn 85.26 71.87 87.36 81.71 Soybean meal, 46.5% CP 16.62 31.13 13.15 24.69 Soybean meal, 46.5% CP 10.94 24.69 10.19 14.90 Corn oil 1.65 1.00 1.40 1.00 Corn oil 1.50 1.00 0.40 0.90 Limestone 1.00 0.98 0.80 0.78 Limestone 0.80 0.78 0.80 0.80 Monocalcium P, 21% P 0.90 0.70 0.58 0.43 Monocalcium P, 21% P 0.60 0.43 0.55 0.50 Sodium chloride 0.50 0.50 0.50 0.50 Sodium chloride 0.50 0.50 0.50 0.50 L-Lys-HCl 0.28 0.33 0.19 0.28 L-Lys-HCl 0.17 0.28 — 0.30 DL-Met 0.03 0.13 0.02 0.10 DL-Met — 0.10 — 0.05 L-Thr 0.08 0.12 0.04 0.11 L-Thr 0.03 0.11 — 0.11 L-Trp 0.02 0.01 0.01 0.01 L-Trp — 0.01 — 0.02 L-Val 0.01 0.06 0.01 0.05 L-Val — 0.05 — 0.02 3 3 Vitamin premix with phytase 0.15 0.15 0.10 0.10 Vitamin premix with phytase 0.10 0.10 0.10 0.10 4 4 Trace mineral premix 0.15 0.15 0.10 0.10 Trace mineral premix 0.10 0.10 0.10 0.10 Total 100 100 100 100 Total 100 100 100 100 5 5 Calculated analysis Calculated analysis SID AA, % SID AA, % Lys, % 0.80 1.20 0.65 1.00 Lys, % 0.58 1.00 0.43 0.78 Ile:Lys 62 62 68 64 Ile:Lys 70 64 92 60 Leu:Lys 148 128 171 139 Leu:Lys 183 139 245 148 Met:Lys 31 34 33 35 Met:Lys 33 35 44 33 Met and Cys:Lys 58 58 65 61 Met and Cys:Lys 67 61 89 60 Thr:Lys 63 63 66 65 Thr:Lys 66 65 81 66 Trp:Lys 19 19 19 19 Trp:Lys 18 19 24 19 Val:Lys 72 72 80 75 Val:Lys 82 75 109 72 His:Lys 44 41 49 43 His:Lys 51 43 68 43 Total Lys, % 0.91 1.34 0.75 1.13 Total Lys, % 0.67 1.13 0.52 0.88 NE, kcal/kg 2,698 2,698 2,698 2,703 NE, kcal/kg 2,698 2,703 2,577 2,579 SID Lys:NE, g/Mcal 2.96 4.45 2.41 3.70 SID Lys:NE, g/Mcal 2.15 3.70 1.57 3.02 SID Lys:CP, % 5.42 5.79 4.87 5.51 SID Lys:CP, % 4.67 5.51 3.57 5.47 CP, % 14.8 20.7 13.4 18.1 CP, % 12.4 18.1 12.1 14.3 Ca, % 0.67 0.67 0.51 0.51 Ca, % 0.51 0.51 0.50 0.50 P, % 0.52 0.54 0.43 0.45 P, % 0.43 0.45 0.42 0.43 STTD P, % 0.40 0.40 0.32 0.32 STTD P, % 0.32 0.32 0.31 0.31 1 1 Diets were fed from 36.3 to 54.2 kg BW.The twodiets were blended to Diets were fed from 76.4 to 99.1 kg BW. The two diets were blended to create intermediate treatment diets containing 0.88, 0.96, 1.04, and 1.12% create intermediate treatment diets containing 0.65%, 0.72%, 0.79%, SID Lys, respectively. 0.86%, and 0.93% SID Lys, respectively. 2 2 Diets were fed from 53.2 to 74.2 kg BW.The twodiets were blended to Diets were fed from 103.8 to 127.3 kg BW. The two diets were blended to create intermediate treatment diets containing 0.72, 0.79, 0.86, and 0.93% create intermediate treatment diets containing 0.50%, 0.57%, 0.64%, and SID Lys, respectively. 0.71% SID Lys, respectively. 3 3 Ronozyme Hiphos (GT) 2700 (DSM Nutritional Products, Inc, Ronozyme Hiphos (GT) 2700 (DSM Nutritional Products, Inc., Parsippany NJ), provided 748 or 500 phytase units (FYT/kg), for an Parsippany NJ), provided 500 phytase units (FYT/kg), for an estimated estimated release of 0.10 or 0.09% STTD P, in experiments 2 and 3, release of 0.09% STTD P. Provided per kilogram of premix: 1,653,465 IU respectively. Provided per kilogram of premix: 1,653,465 IU Vitamin A, vitamin A, 661,386 IU vitamin D , 17,637 IU vitamin E, 1323 mg vitamin 661,386 IU Vitamin D , 17,637 IU Vitamin E, 1323 mg Vitamin K, 13 mg K, 13 mg vitamin B , 19,842 mg niacin, 11,023 mg pantothenic acid, 3 12 Vitamin B , 19,842 mg niacin, 11,023 mg pantothenic acid, 3,306 mg 3,306 mg menadione. menadione. Provided per kilogram of premix: 11 g Cu, 0.2 g I, 73 g Fe, 22 g Mn, 0.2 g Provided per kilogram of premix: 11 g Cu, 0.2 g I, 73 g Fe, 22 g Mn, 0.2 g of Se, 73 g Zn. of Se, 73 g Zn. Ingrdient values and SID coefficients were derived from NRC (2012). Ingrdient values and SID coefficients were derived from NRC (2012). ($236/tonne); soybean meal = $440/tonne; L-Lys at $1.76/kg; DL-Met at $5.51/kg; L-Thr at $2.65/kg; L-Trp at $11.02/kg; feed intake × diet cost ($/kg). Feed cost/kg of gain was calcu- and L-Val at $8.82/kg. Low-priced diet costs were determined lated using feed cost/pig divided by total gain. Revenue per using the following ingredient prices: corn = $3.00/bushel pig was determined for both a high and a low price by total ($118/tonne); soybean meal = $330/tonne; L-Lys at $1.43/kg; gain × $1.46/kg live gain, or total gain × $0.99/kg live gain, DL-Met at $3.75/kg; L-Thr at $1.87/kg; L-Trp at $6.61/kg; respectively. Income over feed cost was calculated using rev- and L-Val at $5.51/kg. Feed cost/pig was determined by total enue/pig—feed cost/pig. Lysine requirement of grow-finish pigs 5 Statistical Analysis lowest breakpoint suggested by the dose response models (ADG or G:F) was selected. In experiment 4, the midpoint Data were analyzed as an RCBD for a one-way ANOVA between the two suggested breakpoints was used. In exper- using the lmer function from the lme4 package in R Studio iment 5, the highest breakpoint suggested by the dose–re- (Version 3.5.2, R Core Team; Vienna, Austria) with pen sponse models was selected. The suggested requirement for serving as the experimental unit, pen average BW as blocking maximum growth performance from each experiment was factor, and treatment as fixed effect. Dose–response curves used to develop the regression equation. For economic re- were evaluated using linear (LM), quadratic polynomial turn, the highest breakpoint suggested by the dose–response (QP), and broken-line linear (BLL) models. For each re- models was used to develop the regression equation. These sponse variable, the best-fitting model was selected using curves describe the Lys:calorie ratio that best met biological the Bayesian Information Criterion (BIC). A decrease in BIC requirements for growth performance and optimized IOFC greater than 2.0 among models for a particular response in this series of trials (Figure 1) criterion was considered an improved fit. Results were considered significant with P ≤ 0.05 and were considered marginally significant with P ≤ 0.10. The predicted require- RESULTS ment for maximum growth performance and economic re- Experiment 1 turn found from dose response curves in each study were used to develop regression equations to predict the overall In 18- to 40-kg pigs, increasing SID Lys increased d 24 BW Lys:calorie ratio required for maximum growth perfor- (linear, P ≤ 0.04; Table 6). Overall ADG increased with mance and economic return. In experiments 1, 2, and 3, the increasing SID Lys (linear, P = 0.003). Pigs fed increasing SID Lys had decreased (linear, P = 0.012) ADFI from d 0 to 24. An improvement for overall G:F (linear, P < 0.001) Table 4. Amino acid analysis of diets (experiment 1; as-fed basis) was observed with increasing SID Lys. Daily SID Lys intake and Lys intake per kg of gain increased (linear, P < 0.001) SID Lys, % with increasing SID Lys. For economic analysis, feed cost and feed cost per kg of gain increased (linear, P < 0.001), Item 1.00 1.10 1.20 1.30 1.40 1.50 while total revenue tended to decrease (linear, P = 0.074) Amino acid analysis, % with increasing SID Lys at both high and low ingredient Lys 1.16 1.30 1.34 1.48 1.52 1.64 pig prices. At high ingredient and pig prices, there was no evidence of significant difference ( P > 0.10) for IOFC. Ile 0.74 0.81 0.76 0.87 0.90 0.95 However, at low ingredient and pig prices, increasing SID Met 0.35 0.40 0.38 0.45 0.50 0.53 Lys decreased (linear, P = 0.048) IOFC, with pigs fed diets Met + Cys 0.64 0.71 0.70 0.80 0.83 0.89 containing 1.10% SID Lys having the greatest numeric Thr 0.79 0.88 0.90 1.02 1.05 1.11 IOFC. Trp 0.24 0.25 0.28 0.31 0.31 0.33 Dose–response curves were evaluated for overall growth Val 0.83 0.91 0.88 1.00 1.07 1.14 performance, and when modeling ADG, the LM and QP His 0.48 0.51 0.50 0.55 0.55 0.59 models resulted in a comparable fit. The QP model equation Phe 0.98 1.04 1.02 1.12 1.13 1.17 was: ADG = −0.282148 × (SID Lys, %) + 0.797053 × (SID Lys, %) + 0.339, with maximum ADG estimated at 1.41% 1 rd Diet samples were taken from every 3 bag of feed 7 d after the beginning SID Lys (Supplementary Figure S1A). For the LM, maximum of the trial and stored at -20°C. Values are reported on a total analyzed ADG was predicted above 1.50% SID Lys. For G:F, the LM basis. Composite sample was submitted to Ajinomoto Heartland Inc. (Eddyville, resulted in the best fit, and predicted maximum feed efficiency IA) for amino acid analysis. above 1.50% SID Lys (Supplementary Figure S1B). Table 5. Amino acid analysis of diets (experiment 2, 3, 4, and 5; as-fed basis) experiment 2 experiment 3 experiment 4 experiment 5 SID Lys, % SID Lys, % SID Lys, % SID Lys, % Item 0.80 1.20 0.65 1.00 0.58 1.00 0.43 0.79 Amino acid analysis, % Lys 0.95 1.26 0.83 1.19 0.78 1.18 0.55 1.15 Ile 0.58 0.80 0.52 0.74 0.49 0.75 0.48 0.75 Met 0.25 0.41 0.22 0.35 0.19 0.33 0.23 0.34 Met + Cys 0.43 0.69 0.45 0.64 0.39 0.61 0.44 0.63 Thr 0.59 0.76 0.49 0.72 0.44 0.65 0.46 0.73 Trp 0.17 0.25 0.15 0.22 0.12 0.22 0.14 0.24 Val 0.69 0.93 0.64 0.87 0.59 0.87 0.61 0.86 His 0.43 0.56 0.40 0.53 0.39 0.53 0.31 0.47 Phe 0.81 1.05 0.74 0.98 0.68 1.01 0.62 0.94 Diet samples were taken from 6 feeders 3 d after the beginning of the trial and stored at -20°C. Values are reported on a total analyzed basis. Composite sample was submitted to Ajinomoto Heartland Inc. (Eddyville, IA) for amino acid analysis. 6 Royall et al. When modeling IOFC at high ingredient and pig prices, the and pig prices, the LM and BLL models had a similar fit to LM model resulted in the best fit and predicted the SID Lys re - maximize IOFC. The LM estimated maximum IOFC at less quirement to achieve maximum IOFC was at less than 1.00% than 1.00% SID Lys, while the BLL model predicted similar (Supplementary Figure S1C). Meanwhile, at low ingredient IOFC from 1.00 to 1.12% SID Lys with a reduction in IOFC when SID Lys increased past 1.12% (Supplementary Figure S1D). Experiment 2 In 36 to 54 kg pigs, increasing SID Lys did not significantly affect (P > 0.10) final BW ( Table 7). However, ADG increased (linear, P = 0.036) with increasing SID Lys, while there was no observed difference (P > 0.10) in ADFI. As a result, increasing SID Lys increased (linear, P < 0.001) G:F. Daily SID Lys intake and Lys intake per kg of gain increased (linear, P < 0.001) with increasing SID Lys. For economic analysis, feed cost and feed cost per kg of Figure 1. Optimal Lys:calorie ratio (g of Lys/Mcal of NE) prediction gain increased (linear, P < 0.002), and revenue tended to equations were developed for maximum growth performance and IOFC for 18 to 128 kg pigs using our interpretation of 5 trials conducted to increase (linear, P = 0.060) with increasing SID Lys at both determine the maximum SID Lys, % for Duroc-sired pigs (600 × 241, high and low ingredient and pig prices. At high ingredient and DNA) fed in a university research environment. Barrows and gilts were pig prices, there was no evidence of difference (P > 0.10) for penned together with gender equalized by block. To maximize growth IOFC. However, at low ingredient and pig prices, increasing performance, the quadratic equation is Lys:calorie ratio, g of SID Lys/ SID Lys tended to decrease (linear, P = 0.097) IOFC, with Mcal of NE = 0.0002611 × BW – 0.0711037 × BW + 7.284. To maximize pigs fed diets containing 0.88% or 0.96% SID Lys having the IOFC, the quadratic equation is Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0001558 × BW − 0.04030769 × BW + 5.410. greatest numeric IOFC. Table 6. Effects of increasing SID Lys on growth performance of pigs weighing 18 to 40 kg (experiment 1) SID Lys, % P = Item 1.00 1.10 1.20 1.30 1.40 1.50 SEM Linear Quadratic BW, kg d 0 18.4 18.5 18.4 18.4 18.4 18.4 0.50 0.918 0.863 d 24 39.0 39.9 39.9 39.6 40.1 40.2 0.86 0.040 0.537 Overall (d 0to24) ADG, g 844 889 895 888 894 907 17.0 0.003 0.166 ADFI, g 1,477 1,468 1,472 1,429 1,445 1,411 31.2 0.012 0.676 G:F, g/kg 572 605 609 622 620 643 6.4 < 0.001 0.212 SID Lys g/d 14.74 16.12 17.63 18.53 20.19 21.12 0.386 < 0.001 0.470 SID Lys g/kg gain 17.46 18.15 19.69 20.87 22.59 23.28 0.218 < 0.001 0.719 Economics, $ High ingredient and pig prices Feed cost/pig 11.91 12.49 12.73 12.92 13.47 13.64 0.314 < 0.001 0.702 Feed cost/kg gain 0.583 0.573 0.592 0.602 0.628 0.625 0.0064 < 0.001 0.272 Total revenue/pig 29.82 31.85 31.37 31.33 31.32 31.83 0.689 0.074 0.265 IOFC 17.91 19.36 18.64 18.41 17.85 18.20 0.429 0.304 0.169 Low ingredient and pig prices Feed cost/pig 7.54 7.99 8.22 8.42 8.85 9.03 0.203 < 0.001 0.673 Feed cost/lb gain 0.369 0.366 0.383 0.392 0.413 0.414 0.0019 < 0.001 0.339 Total revenue/pig 20.22 21.60 21.27 21.24 21.24 21.59 0.467 0.074 0.265 IOFC 12.68 13.61 13.05 12.82 12.38 12.56 0.300 0.048 0.181 A total of 300 pigs (DNA 600 × 241; initially 18.4 ± 0.50 kg BW) were used with 5 pigs per pen and 10 replications per treatment. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig—feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. Lysine requirement of grow-finish pigs 7 Dose–response curves for overall growth performance re- (Supplementary Figure S3A). The QP model resulted in the vealed that LMs were the best fit for ADG and G:F, with the best fit to optimize feed efficiency. The QP model equation SID Lys requirement to maximize ADG and G:F predicted was: G:F = −0.4830938 × (SID Lys, %) + 0.9555893 × (SID above 1.20% (Supplementary Figure S2A and S2B). At both Lys, %) – 0.027 with maximal G:F estimated at 0.99% SID high and low ingredient and pig prices, LMs resulted in the Lys (Supplementary Figure S3B). When modeling IOFC at high best fit for IOFC, with maximum IOFC estimated at <0.80% ingredient and pig prices, the BLL model resulted in the best SID Lys (Supplementary Figure S2C and S2D). fit, predicting no further improvement in IOFC past 0.76% SID Lys (Supplementary Figure S3C). Meanwhile, at low in- Experiment 3 gredient and pig prices, the LM and QP models had a compa- In 53 to 75  kg pigs, increasing SID Lys increased (linear, rable fit. The LM predicted maximum IOFC above 1.00% SID P < 0.001) final BW ( Table 8). Average daily gain increased Lys. The QP model equation was: IOFC = −14.5626 × (SID (linear, P < 0.001) with increasing SID Lys while for ADFI, Lys, %) + 26.6348 × (SID Lys, %) −0.085, with maximum there was a quadratic (P = 0.004) decrease with increasing IOFC estimated at 0.91% SID Lys. SID Lys. A linear and quadratic (P < 0.001) response was Experiment 4 observed for overall G:F with increasing SID Lys. Additionally, daily SID Lys intake and Lys intake per kg of gain increased In 76 to 100  kg pigs, increasing SID Lys did not signif- (linear and quadratic, P < 0.003) with increasing SID Lys. icantly affect (P > 0.10) final BW ( Table 9). Average daily For economic analysis, feed cost increased (linear and gain increased (linear, P = 0.022) with increasing SID Lys, quadratic, P < 0.023), while feed cost per kg of gain decreased while there was no observed difference (P > 0.10) in ADFI. (linear and quadratic, P < 0.012) with increasing SID Lys in As a result, increasing SID Lys numerically increased (quad- both economic scenarios. Meanwhile, at both high and low ratic, P < 0.10) G:F. with no improvement in G:F feeding ingredient and pig prices, increasing SID Lys increased line- beyond 0.86% SID Lys. Daily SID Lys intake and Lys intake arly (P < 0.002) revenue and IOFC. per kg of gain increased (linear, P < 0.001) with increasing Dose–response curves were evaluated for overall growth SID Lys. For economic analysis, feed cost increased (linear, performance with the LM being the best fitting model for P < 0.001), and feed cost per kg of gain increased (linear ADG, predicting maximum ADG above 1.00% SID Lys and quadratic, P < 0.041) with increasing SID Lys in both Table 7. Effects of increasing SID Lys on growth performance of pigs weighing 36 to 54 kg (experiment 2) SID Lys, % P Item 0.80 0.88 0.96 1.04 1.12 1.20 SEM Linear Quadratic BW, kg Initial 36.3 36.4 36.3 36.4 36.4 36.2 0.91 0.826 0.634 Final 53.9 54.0 54.2 54.3 54.2 54.4 0.93 0.316 0.806 ADG, kg 0.99 0.99 1.01 1.02 1.01 1.03 0.019 0.036 0.952 ADFI, kg 2.03 1.96 1.98 2.01 1.95 1.98 0.032 0.308 0.399 G:F 0.490 0.507 0.512 0.508 0.521 0.522 0.0108 <0.001 0.374 SID Lys g/d 16.20 17.24 18.98 20.89 21.83 23.82 0.336 <0.001 0.505 SID Lys g/kg gain 16.24 17.17 18.58 20.75 21.69 22.94 0.624 <0.001 0.963 Economics, $ High ingredient and pig prices Feed cost/pig 11.03 10.92 11.27 11.56 11.67 11.99 0.646 <0.001 0.357 Feed cost/kg gain 0.639 0.629 0.641 0.655 0.654 0.666 0.0141 0.002 0.424 Total revenue/pig 25.61 25.75 26.13 26.114 26.24 26.56 1.865 0.060 0.949 IOFC 14.58 14.83 14.86 14.58 14.57 14.57 1.235 0.669 0.624 Low ingredient and pig prices Feed cost/pig 6.73 6.75 7.01 7.32 7.42 7.71 0.406 <0.001 0.373 Feed cost/kg gain 0.390 0.389 0.398 0.415 0.416 0.429 0.0088 <0.001 0.464 Total revenue/pig 17.37 17.46 17.72 17.73 17.79 18.01 1.264 0.060 0.949 IOFC 10.64 10.71 10.71 10.41 10.37 10.29 0.876 0.097 0.659 A total of 608 pigs (600 × 241, DNA; initially 36.3 ± 0.91 kg BW) were used in 2 groups with 7 to 9 pigs per pen and 12 replications per treatment. A total of 285 pigs (initially 38.9 ± 0.81 kg BW) were fed trial diets for a 14-day period for group 1, and 323 pigs (initially 34.1 ± 0.95 kg BW) were fed trial diets for a 21-day period for group 2. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig—feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. 8 Royall et al. Table 8. Effects of increasing SID Lys lysine on growth performance of pigs weighing 53 to 75 kg (experiment 3) SID Lys, % P Item 0.65 0.72 0.79 0.86 0.92 1.00 SEM Linear Quadratic BW, kg d 0 53.1 53.2 53.2 53.2 53.1 53.2 0.86 0.926 0.857 d 21 72.9 73.4 74.1 74.2 74.7 75.7 1.03 <0.001 0.804 Overall (d 0 to 21) ADG, kg 0.94 0.96 1.00 1.01 1.03 1.06 0.017 <0.001 0.910 ADFI, kg 2.42 2.33 2.33 2.32 2.32 2.38 0.048 0.295 0.004 G:F 0.389 0.413 0.429 0.434 0.444 0.447 0.0050 <0.001 0.001 SID Lys g/d 15.79 16.78 18.37 19.97 21.56 23.94 0.396 <0.001 0.003 SID Lys g/kg gain 16.76 17.47 18.43 19.83 20.96 22.58 0.220 <0.001 0.002 Economics, $ High ingredient prices Feed cost/pig 15.04 15.23 15.07 15.53 15.57 16.45 0.344 <0.001 0.023 Feed cost/kg gain 0.760 0.733 0.720 0.727 0.721 0.738 0.0084 0.012 < 0.001 Total revenue/pig 28.89 30.31 30.54 31.20 31.53 32.59 0.568 <0.001 0.745 IOFC 13.85 15.07 15.47 15.68 15.96 16.14 0.327 <0.001 0.064 Low ingredient prices Feed cost/pig 8.64 8.78 8.83 9.23 9.34 10.05 0.203 <0.001 0.006 Feed cost/kg gain 0.437 0.422 0.422 0.432 0.432 0.451 0.0050 0.002 <0.001 Total revenue/pig 19.59 20.55 20.71 21.16 21.38 22.10 0.385 <0.001 0.745 IOFC 10.95 11.77 11.88 11.93 12.04 12.05 0.237 0.002 0.062 A total of 700 pigs (DNA 600 × 241; initial BW of 53.2 ± 0.86 kg) were used with 8 to 10 pigs per pen and 12 replications per treatment and were fed trial diets for a 21-d period in two groups. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig—feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. pricing scenarios. Increasing SID Lys tended to increase Experiment 5 (linear, P = 0.051) revenue at both high and low ingredient In 103- to 128-kg pigs, increasing SID Lys increased (linear, and pig prices. For IOFC, increasing SID Lys did not have a P = 0.025) final BW ( Table 10). Average daily gain increased significant effect ( P > 0.10) in either pricing scenario, how- linearly (P = 0.043) with increasing SID Lys, while there ever, pigs fed diets containing 0.65% or 0.72% SID Lys had was no observed difference (P > 0.10) in ADFI. As a result, the greatest numeric IOFC. increasing SID Lys increased (quadratic, P < 0.032) G:F, with When modeling dose–response curves for ADG, the pigs fed diets containing 0.71% SID Lys having the greatest BLL and LM models resulted in a comparable fit. The BLL numeric G:F. Daily SID Lys intake and Lys intake per kilo- model predicted no further improvement in ADG above gram of gain increased (linear, P < 0.001) with increasing SID 0.83% SID Lys, while the LM estimated maximum ADG Lys. above 1.00% (Supplementary Figure S4A). For G:F, the LM For economic analysis, at high ingredient and pig prices and QP models resulted in a comparable fit, with the LM there was no significant difference between treatments for predicting maximum G:F at greater that 1.00% SID Lys. feed cost per pig (P > 0.10). However, at low ingredient and The QP equation model was: G:F = -0.2244707 × (SID Lys, pig prices, increasing SID Lys increased (linear, P = 0.014) %) + 0.4156878 × (SID Lys, %) + 0.190, with 100% of max- feed cost per pig. At high prices, increasing SID Lys had a imum G:F estimated at 0.93% SID Lys (Supplementary Figure quadratic effect (P = 0.032) on feed cost per kg of gain. S4B). When modelling IOFC at high ingredient and pig prices, Meanwhile at low ingredient and pig prices, increasing SID the QP was the best fitting model. The QP model equation Lys increased (linear, P = 0.044) feed cost per kg of gain. In was: IOFC = -17.3293 × (SID Lys, %) + 27.0408 × (SID Lys, both economic scenarios, increasing SID Lys increased (linear, %) + 4.169, with maximum IOFC estimated at 0.78% SID P = 0.028) revenue. At high ingredient and pig prices, IOFC Lys (Supplementary Figure S4C). However, at low ingredient increased (linear and quadratic, P < 0.020) with increasing and pig prices, the BLL and LM models resulted in a compa- SID Lys. Additionally, increasing SID Lys had a quadratic ef- rable fit. The BLL model predicted a reduction in IOFC when fect (P = 0.004) on IOFC at low ingredient and pig prices, SID Lys increased past 0.76%, while the LM model estimated with pigs fed diets containing 0.71% SID Lys having the maximum IOFC at less than 0.58% SID Lys. greatest numeric IOFC in each scenario. Lysine requirement of grow-finish pigs 9 Table 9. Effects of increasing SID Lys on growth performance of pigs weighing 76 to 100 kg (experiment 4) SID Lys, % P Item 0.58 0.65 0.72 0.79 0.86 0.92 1.00 SEM Linear Quadratic BW, kg d 0 76.5 76.5 76.2 76.5 76.4 76.2 76.2 1.24 0.499 0.936 d 21 98.4 99.0 98.7 99.3 99.4 99.3 99.3 1.37 0.290 0.538 Overall (d 0 to 21) ADG, kg 1.04 1.06 1.07 1.09 1.09 1.10 1.10 0.026 0.022 0.488 ADFI, kg 2.94 2.92 2.89 2.88 2.86 2.89 2.88 0.067 0.357 0.423 G:F 0.355 0.365 0.371 0.378 0.383 0.380 0.382 0.0084 <0.001 0.097 SID Lys g/d 16.92 18.96 20.79 22.78 24.50 26.91 28.65 0.527 <0.001 0.874 SID Lys g/kg gain 16.30 17.82 19.43 20.96 22.52 24.54 26.15 0.472 <0.001 0.398 Economics, $ High ingredient and pig prices Feed cost/pig 17.91 18.29 18.53 18.69 18.94 19.42 19.91 0.470 <0.001 0.527 Feed cost/kg gain 0.824 0.810 0.815 0.819 0.826 0.844 0.864 0.0178 0.008 0.038 Total revenue/pig 31.79 32.98 33.29 33.28 33.51 33.65 33.84 0.836 0.051 0.405 IOFC 13.64 14.69 14.69 14.66 14.58 14.23 14.21 0.676 0.822 0.151 Low ingredient and pig prices Feed cost/pig 10.03 10.51 10.68 10.95 11.26 11.66 12.15 0.274 <0.001 0.486 Feed cost/kg gain 0.461 0.465 0.470 0.480 0.491 0.506 0.527 0.0105 <0.001 0.041 Total revenue/pig 21.55 22.36 22.57 22.57 22.73 22.82 22.95 0.567 0.051 0.405 IOFC 11.34 11.85 11.84 11.66 11.47 11.16 11.03 0.464 0.209 0.172 A total of 616 pigs (600 × 241, DNA; initially 76.4 ± 1.24 kg BW) were used in 2 groups with 8 to 10 pigs per pen and 6 replications for the 0.58% SID Lys treatment; 11 replications for the 0.65%, 0.72%, 0.79%, 0.86%, and 0.92% SID Lys treatments; and 5 replications for the 1.00% SID Lys treatment. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/ total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig—feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. When modelling dose response curves for ADG and G:F, Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0001558 × BW BLL models resulted in the best fit. The BLL model for max - − 0.04030769 × BW + 5.410 was developed. imum ADG predicted no further improvement past 0.64% SID Lys (Supplementary Figure S5A). Meanwhile, the BLL model for maximum G:F estimated no further improvement DISCUSSION above 0.59% SID Lys (Supplementary Figure S5B). When Essential AA requirements for growing-finishing pigs are modeling IOFC at high or low ingredient and pig prices, the commonly based on ratios to Lys. As a result, it is critical QP model resulted in the best fit. At high ingredient and pig to have an accurate estimation of Lys requirements to maxi- prices, the QP model equation was: IOFC = −42.6028 × (SID mize growth performance and optimize feed cost throughout Lys, %) + 54.9097 × (SID Lys, %) – 4.047, with max- the growing-finishing period ( Soto et al., 2019). Moreover, imum IOFC predicted at 0.64% SID Lys (Supplementary continuous advancements in modern pig genetics have led Figure S5C). Additionally, at low ingredient ant pig prices, to increased potential for growth performance and pro- the QP model equation was: IOFC = −25.9430 × (SID Lys, tein accretion, potentially leading to increased dietary nu- %) + 32.4160 × (SID Lys, %) + 0.901, with maximum IOFC trient requirements (O’Connell et al., 2006). Additionally, estimated at 0.62% SID Lys (Supplementary Figure S5D). advancements in dose–response models have provided a strategy to estimate nutrient requirements more accurately Prediction Equations (Gonçalves et al., 2016). This trend in genetic improvement, A summary of the optimum Lys:calorie ratio observed in each coupled with technological improvements to help optimize trial as well as the associated SID Lys intake per day and per health status, environmental conditions, and management kg of gain are provided in Table 11. These values were used to plans, has allowed for improvements in growth performance develop regression equations to predict the Lys:calorie ratio and carcass composition. Between 1980 and 2019, the av- required for maximum growth performance and IOFC of 18- erage market weight of pigs has increased by 18 kg (National to 128-kg pigs (Figure 1). To maximize growth performance, Pork Board, 2016, 2020). Coupled with this increased market the quadratic equation of Lys:calorie ratio, g of SID Lys/ weight, pigs have become more efficient. Between 1990 and Mcal of NE = 0.0002611 × BW – 0.0711037 × BW + 7.284 2019 average growth rate of wean-to-finish pigs increased was developed. To optimize IOFC, the quadratic equation of from 0.58 to 0.80  kg/day, while feed intake per kg of gain 10 Royall et al. Table 10. Effects of increasing SID Lys on growth performance of pigs weighing 103 to 128 kg (experiment 5) SID Lys, % P= Item 0.43 0.50 0.57 0.64 0.71 0.78 SEM Linear Quadratic BW, kg Initial 103.8 103.8 103.9 103.6 103.8 103.8 1.32 0.980 0.966 Final 125.9 127.3 127.0 127.6 128.4 127.3 1.14 0.025 0.102 ADG, kg 0.90 0.95 0.94 0.98 1.00 0.95 0.0256 0.043 0.108 ADFI, kg 3.01 3.01 2.90 2.96 2.98 2.89 0.049 0.102 0.956 G:F 0.300 0.315 0.325 0.329 0.334 0.331 0.064 <0.001 0.032 SID Lys, g/d 12.90 15.03 16.52 18.93 21.12 22.60 0.279 <0.001 0.408 SID Lys, g/kg gain 14.43 15.87 17.54 19.48 21.30 23.75 0.376 <0.001 0.178 Economics, $ High ingredient and pig prices Feed cost/pig 20.37 20.86 20.37 21.46 21.89 21.90 0.920 0.115 0.915 Feed cost/kg gain 0.927 0.898 0.884 0.894 0.895 0.922 0.0082 0.929 0.032 Total revenue/pig 32.01 33.84 33.56 34.96 35.62 34.54 1.07 0.028 0.229 IOFC 11.63 12.98 13.18 13.52 13.73 12.65 0.450 0.020 0.001 Low ingredient and pig prices Feed cost/pig 11.73 12.06 12.07 12.75 13.13 13.17 0.544 0.014 0.957 Feed cost/kg gain 0.534 0.519 0.524 0.531 0.537 0.555 0.0107 0.044 0.077 Total revenue/pig 21.70 22.95 22.75 23.71 24.15 23.42 0.724 0.028 0.229 IOFC 9.97 10.89 10.69 10.98 11.02 10.25 0.324 0.397 0.004 A total of 679 pigs (600 × 241, DNA; initial BW of 228.8 ± 2.9 lb) were used with 8 to 10 pigs per pen and 12 replications per treatment for the 0.43%, 0.50%, 0.57%, 0.71%, and 0.78% SID Lys treatments, 11 replications for the 0.64% SID Lys treatment, and were fed trial diets for a 21- or 28-d period in two groups. Each pen contained both barrows and gilts and gender equalized by block. For high priced diets, corn was valued at $6.00/bu ($235.71/tonne), soybean meal at $440/tonne, L-Lys at $1.76/kg, DL-Met at $5.51/kg, L-Thr at $2.65/ kg, L-Trp at $11.02/kg, and L-Val at $8.82/kg. Feed cost/lb gain = (feed cost/pig)/ total gain. Total revenue/pig = total gain/pig × gain value ($1.46/kg at high prices; $0.99/kg at low prices). Income over feed cost = total revenue/pig – feed cost/pig. For low priced diets, corn was valued at $3.00/bu ($117.86/tonne), soybean meal at $330/tonne, L-Lys at $1.43/kg, DL-Met at $3.75/kg, L-Thr at $1.87/ kg, L-Trp at $6.61/kg, and L-Val at $5.51/kg. Table 11 Summary of the Lys:calorie ratio and associated SID Lys percentage and Lys intake that provided maximal response for growth performance and income over feed cost (IOFC) Trial BW range, kg Midpoint BW, kg Lys:calorie ratio, g of SID SID Lys, % SID Lys intake, g/d SID Lys g/kg of gain Lys/Mcal of NE Growth performance Trial 1 18 to 40 29 5.53 1.41 20.37 22.63 Trial 2 36 to 54 46 4.45 1.20 23.80 22.90 Trial 3 53 to 75 64 3.70 0.99 23.56 22.55 Trial 4 76 to 100 88 3.26 0.88 25.30 23.11 Trial 5 103 to 128 116 2.48 0.64 18.93 19.48 IOFC Trial 1 18 to 40 29 4.39 1.12 16.46 18.46 Trial 2 36 to 54 46 3.56 0.96 19.00 18.60 Trial 3 53 to 75 64 3.37 0.91 21.11 20.20 Trial 4 76 to 100 88 2.89 0.78 22.50 20.84 Trial 5 103 to 128 116 2.48 0.64 18.93 19.48 Five trials were conducted to determine maximum SID Lys,% in grow-finish pigs (600 × 241, DNA). Income over feed cost = total revenue/pig—feed cost/pig. decreased from 3.2 to 2.6  kg during that same time frame Estimations of dietary Lys requirements for growing- (National Pork Board, 2020; PigChamp, 1990). Similarly, this finishing pigs have changed considerably in the last 30 years. improved growth performance was observed in our study, as Cromwell et al. (1993) suggested that the total Lys require- pigs grew at an average between 0.89 and 1.08 kg/day across ment for barrows and gilts from 35 to 105 kg was 0.60% and our 5 experiments. 0.90%, respectively. Hahn et al. (1995) suggested a total Lys Lysine requirement of grow-finish pigs 11 requirement for barrows and gilts weighing between 90 and performance when they weigh less than 100 kg. However, in 110 kg of 0.49% and 0.52%, respectively. More recently, in late-finishing pigs (103 to 128 kg), maximum economic per - a meta-analysis with PIC (Hendersonville, TN) genetic lines, formance is achieved at similar levels as maximum growth Gonçalves et al. (2017) suggested that the SID Lys require- performance. ment for barrows and gilts in predominantly Pietrain-sired In conclusion, the SID Lys estimate for maximum IOFC and pigs was 1.11% and 1.16% (25 to 50 kg), 0.91% and 0.94% growth performance was determined for 5 different weight (50 to 75 kg), 0.78% and 0.80% (75 to 100 kg), and 0.70% ranges from 18 to 128 kg. In addition, prediction equations and 0.75% (100 to 135  kg), respectively. Soto et al. (2019) were developed to describe the Lys:calorie ratio that best observed that late finishing pigs (102 to 128 kg) grown in the met biological requirements for growth performance and same facilities with similar genetic maternal and paternal lines optimized IOFC. Therefore, this data can be used to formu- as our study achieved maximum ADG and G:F at 0.62% and late SID Lys diet levels for Duroc-sired pigs ranging in weight 0.63% SID Lys, respectively. In our study, the SID Lys estimate from 18 to 128 kg. for maximum growth performance was 1.41% to 1.50%, at least 1.20%, 0.99% to 1.00%, 0.83% to 0.93%, and 0.59% SUPPLEMENTARY DATA to 0.64% for pigs weighing 18 to 40 kg, 36 to 54 kg, 53 to 75 kg, 76 to 100 kg, and 103 to 128 kg, respectively. Supplementary data are available at Translational Animal During the grower period (25 to 50 kg) we observed con- Science online. siderably higher estimates than those of Gonçalves et al. Supplementary Figure S1. Estimation of standardized ileal (2017). This difference may be a result of drastic differences digestible (SID) lysine requirement to maximize ADG, G:F, in daily feed intake (2.31  kg/day in Gonçalves vs. 1.99  kg/ and income over feed cost (IOFC) for 18 to 40 kg Duroc-sired day in current study). Pigs in our study may have required pigs (600 × 241, DNA; Exp. 1). A total of 300 pigs (600 × 241, a considerably higher SID Lys percentage in the diet to DNA; initially 18.4 ± 0.50  kg) were used in a 24-d growth meet a similar Lys intake per kg of gain. Similarly, in pigs trial with 5 pigs per pen and 10 replications per treatment. weighing between 50 and 100 kg, we observed higher lysine Barrows and gilts were penned together with gender equalized requirements than those of Gonçalves et al. (2017). In late by block. A. The linear model (LM) and quadratic polynomial finishing (103 to 128 kg pigs), we observed a similar SID Lys (QP) models had a comparable fit (BIC = -184.9 and -182.9, requirement to those of Soto et al. (2019), which was consid- LM and QP, respectively) with the SID Lys requirement to erably lower than those of Gonçalves et al. (2017). Variation achieve maximal ADG predicted above 1.50% with LM and in Lys requirements among studies could be attributable to 1.41% with the QP model. The QP model equation was: differences in genetic capability for protein deposition, amino ADG = -0.282148 × (SID Lys, %) + 0.797053 × (SID Lys, acid digestibility, or immune stress (Kendall et al., 2007). %) + 0.339. B. The LM had the best fit with the SID Lys re - The present studies were conducted under a controlled, high- quirement to achieve maximal feed efficiency predicted above health research environment. Thus, Lys requirement estimates 1.50% C. The LM was the best fitting model with the SID Lys might change with different environmental conditions. requirement to achieve maximal IOFC with high ingredient Lysine requirements are often expressed as a function of and pig prices predicted at less than 1.00% SID Lys. D. The SID Lys required per kg of BW gain. Our estimated require- LM and BLL models had a comparable fit (BIC = 178.0 and ment ranged from approximately 22.6 to 23.3 g SID Lys/kg 179.4, LM and BLL, respectively) with the SID Lys require- gain for 18 to 75 kg pigs and from 21.3 to 22.5 g SID Lys/ ment to achieve maximal IOFC with low ingredient and pig kg gain for 76 to 128 kg pigs. In comparison, Shelton et al. prices predicted at less than 1.00% with the LM, and 1.12% (2011) and Main et al. (2008) observed a requirement ranging with the BLL model. The BLL model predicted a reduction in between 19.6 and 23.0  g SID Lys/kg gain in pigs weighing IOFC when SID Lys increased past 1.12% SID Lys. 35 to 110  kg. Additionally, Main et al. (2008) and Soto et Supplemental Figure S2. Estimation of standardized ileal al. (2019) observed a requirement ranging between 17.0 and digestible (SID) lysine requirement to maximize ADG, G:F, 22.6 g SID Lys/kg gain in pigs weighing 100 to 130 kg. The and income over feed cost (IOFC) for 36 to 54  kg Duroc- increased requirement of SID Lys intake per kg of BW gain sired pigs (600 × 241, DNA; Exp. 2). A total of 608 pigs observed in our trials may be a result of pigs depositing a (600 × 241, DNA; initially 36.3 ± 0.91  kg BW) were used higher proportion of protein rather than lipids compared to with in a pair of 14 or 21-d growth trials, with 7 to 9 pigs previous research. per pen and 12 replications per treatment. Barrows and gilts Economic analysis, as well as growth performance, is were penned together with gender equalized by block. A. The vital when developing nutritional programs. Income over linear model (LM) was the best fitting model with the SID Lys feed cost accounts for the gross sale revenue and feed ex- requirement to achieve maximal ADG predicted at greater pense generated. Multiple studies have observed that nutrient than 1.20% SID Lys. B. The LM was the best fitting model requirements to maximize biological performance may align with the SID Lys requirement to achieve maximal feed effi - with optimal IOFC estimates (De La Llata et al., 2001; Main ciency predicted at greater than 1.20% SID Lys. C. The LM et al., 2008). In contrast, our results in experiments 1, 2, 3, was the best fitting model with the SID Lys requirement to and 4 (18 to 100 kg pigs) suggest that the SID Lys require- achieve maximal IOFC with high ingredient and pig prices ment to optimize IOFC is considerably lower than the biolog- predicted at less than 0.80% SID Lys. D. The LM was the best ical requirement for maximal growth performance. However, fitting model with the SID Lys requirement to achieve maxi - in experiment 5, the SID Lys requirement for maximum IOFC mal IOFC with low ingredient and pig prices predicted at less and growth performance were more closely aligned (0.59% than 0.80% SID Lys. to 0.64%). These results would suggest that, in the economic Supplemental Figure S3. Estimation of standardized ileal scenarios considered in our analysis, there is no economic digestible (SID) lysine requirement to maximize ADG, G:F, advantage to feed pigs to their maximum biological growth and income over feed cost (IOFC) for 53 to 75 kg Duroc-sired 12 Royall et al. pigs (600 × 241, DNA; Exp. 3). A total of 700 pigs (DNA Lys treatment. Barrows and gilts were penned together with 600 × 241; initial BW of 53.2 ± 0.86  kg) were used in two gender equalized by block. A. The broken line linear (BLL) was separate 21-d growth trials, with 8 to 10 pigs per pen and the best fitting model with the SID Lys requirement to achieve 12 replications per treatment. Barrows and gilts were penned maximal ADG predicted at 0.64%. The BLL predicted no fur- together with gender equalized by block. A. The linear model ther improvement in ADG past 0.64% SID Lys. B. The BLL (LM) was the best fitting model with the SID Lys require - was the best fitting model with the SID Lys requirement to a - ment to achieve maximal ADG predicted above 1.00% SID chieve maximal feed efficiency predicted at 0.59%. The BLL Lys. B. The quadratic polynomial (QP) was the best fitting predicted no further improvement in feed efficiency past 0.59% model with the SID Lys requirement to achieve maximal feed SID Lys. C. The quadratic polynomial (QP) was the best fitting efficiency predicted at 0.99%. The QP model equation was: model with the SID Lys requirement to achieve maximal IOFC G:F = -0.4830938 × (SID Lys, %) + 0.9555893 × (SID Lys, at high ingredient and pig prices predicted at 0.64% SID Lys. %) – 0.027. C. The broken line linear (BLL) was the best The QP model equation was: IOFC = -42.60278 × (SID Lys, fitting model with the SID Lys requirement to achieve max - %) + 54.9097 × (SID Lys, %) – 4.047. D. The QP was the best imal IOFC with high ingredient and pig prices predicted at fitting model with the SID Lys requirement to achieve maximal 0.76%. The BLL predicted no further improvement in IOFC IOFC at low ingredient and pig prices predicted at 0.62% SID past 0.76% SID Lys. D. The LM and QP models had a com- Lys. The QP model equation was: IOFC = -25.9430 × (SID Lys, parable fit (BIC = 191.8 and 192.4, LM and QP, respectively) %) + 32.4160 × (SID Lys, %) + 0.901. with the SID Lys requirement to achieve maximal IOFC with low ingredient and pig prices predicted above 1.00% with the LM, and 0.91% with the QP. The QP model equation ACKNOWLEDGMENTS was: IOFC = -14.5626 × (SID Lys, %) + 26.6348 × (SID Lys, Contribution no. 22-102-J of the Kansas Agricultural %) - 0.085. Experiment Station, Manhattan, KS USA 66506-0201. Supplemental Figure S4. Estimation of standardized ileal digestible (SID) lysine requirement to maximize ADG, G:F, and income over feed cost (IOFC) for 76 to 100 kg Duroc- CONFLICT OF INTEREST STATEMENT sired pigs (600 × 241, DNA; Exp. 4). A total of 616 pigs The authors declare no conflict of interest. (600 × 241, DNA; initially 76.4 ± 1.24  kg BW) were used in two separate 21-d growth trials, with 8 to 10 pigs per pen and 6 replications for the 0.58% SID Lys treatment; 11 LITERATURE CITED replications for the 0.65, 0.72, 0.79, 0.86, and 0.92% SID Lys treatments; and 5 replications for the 1.00% SID Lys treat- AOAC International. 2012. Official methods of analysis of AOAC In - ternational. 19th ed. Gaithersburg, MD: Association of Official An - ment. Barrows and gilts were penned together with gender alytical Chemists. equalized by block. A. The broken line linear (BLL) and lin- Campbell, R. G., M. R. Taverner. 1988. Genotype and sex effects on the ear model (LM) models had a comparable fit (BIC = -179.4 relationship between energy intake and protein deposition in grow- and -179.1, BLL and LM, respectively) with the SID Lys re- ing pigs. J. Anim. Sci. 66:676–86. doi:10.2527/jas1988.663676x quirement to achieve maximal ADG predicted at 0.83% with Cemin, Henrique S., Hayden E. Williams, Mike D. Tokach, Steve the BLL, and greater than 1.00% with the LM model. The S. Dritz, Jason C. Woodworth, Joel M. DeRouchey, Robert D. BLL predicted no further improvement in ADG past 0.83% Goodband, Kyle F. Coble, Brittany A. Carrender, and Mandy J. SID Lys. B. The LM and quadratic polynomial (QP) models Gerhart. 2020. Estimate of the energy value of soybean meal rela- had a comparable fit (BIC = -330.1 and -331.0, LM and QP, tive to corn based on growth performance of nursery pigs. J. Anim. respectively) with the SID Lys requirement to achieve maxi- Sci. Biotech. 11:70–79 https://jasbsci.biomedcentral.com/track/ pdf/10.1186/s40104-020-00474-x mal feed efficiency predicted at greater than 1.00% with the Cromwell, G. L., T. R. Cline, J. D. Crenshaw, T. D. Crenshaw, R. C. LM, and 0.93% with the QP model. The QP equation model 2 Ewan, C. R. Hamilton, A. J. Lewis, D. C. Mahan, E. R. Miller, and J. was: G:F = -0.2244707 × (SID Lys, %) + 0.4156878 × (SID E. Pettigrew. 1993. The dietary protein and (or) lysine requirements Lys, %) + 0.190. C. The QP was the best fitting model with of barrows and gilts. NCR-42 committee on swine nutrition. J. the SID Lys requirement to achieve maximal IOFC at high Anim. Sci. 74:93–102. doi:10.2527/1993.7161510x ingredient and pig prices predicted at 0.78% SID Lys. The De La Llata, M., S. S. Dritz, M. R. Langemeier, M. D. Tokach, R. D. QP model equation was: IOFC = -17.3293 × (SID Lys, Goodband, and J. L. Nelssen. 2001. Economics of increasing %) + 27.0408 × (SID Lys, %) + 4.169. D. The BLL and LM lysine:calorie ratio and adding dietary fat for growing-finishing models had a comparable fit (BIC = 202.5 and 202.6, BLL pigs reared in a commercial environment. Swine Health Prod. and LM, respectively) with the SID Lys requirement to achieve 9:215–223. Gonçalves, M. A., N. M. Bello, S. S. Dritz, M. D. Tokach, J. M. maximal IOFC at low ingredient ant pig prices predicted DeRouchey, J. C. Woodworth, and R. D. Goodband. 2016. An at 0.76% with the BLL, and less than 0.58% with the LM update on modeling dose-response relationships: accounting for model. The BLL model predicted a reduction in IOFC when correlated data structure and heterogeneous error variance in SID Lys increased past 0.76% SID Lys. linear and nonlinear mixed models. J. Anim. Sci. 94:1940–1950. Supplemental Figure S5. Estimation of standardized ileal di- doi:10.2527/jas.2015-0106 gestible (SID) lysine requirement to maximize ADG, G:F, and Gonçalves, M. A. D., U. Orlando, W. Cast, and M. Culberson. 2017. income over feed cost (IOFC) for 103 to 128 kg Duroc-sired Standardized ileal digestible lysine requirements for finishing PIC pigs (600 × 241, DNA; Exp. 5). A total of 679 pigs (600 × 241, pigs under commercial conditions: A meta-analysis. J. Anim. Sci. DNA; initial BW of 228.8 ± 2.9 lb) were used in two separate 95(E. Suppl. 2):E131–3132. 21- or 28-d growth trials, with 8 to 10 pigs per pen and 12 Hahn, J. D., R. R. Biehl, and D. H. Baker. 1995. Ideal digestible lysine level for early- and late-finishing swine. J. Anim. Sci. 73:773–84. replications per treatment for the 0.43, 0.50, 0.57, 0.71 and doi:10.2527/1995.733773x 0.78% SID Lys treatments, 11 replications for the 0.64% SID Lysine requirement of grow-finish pigs 13 Kendall, D. C., A. M. Gaines, B. J. Kerr, and G. L. Allee. 2007. True growing-finishing pigs. Livest. Sci. 101:1690179. doi:10.1016/j. ileal digestible tryptophan to lysine ratios in ninety- to one hun- livprodsci.2005.11.024 dred twenty-five-kilogram barrows. J. Anim. Sci. 73:3000–3008. PigChamp. 1990. Grow-finish production values . Webster City, IA: doi:10.2527/jas.2007-0013 Swine Graphics. Main, R. G., S. S. Dritz, M. D. Tokach, R. D. Goodband, and J. L. Shelton, N. W., M. D. Tokach, S. S. Dritz, R. D. Goodband, J. L. Nelssen. 2008. Determining an optimum lysine:calorie ratio for Nelssen, and J. M. DeRouchey. 2011. Effects of increasing dietary barrows and gilts in a commercial finishing facility. J. Anim. Sci. standardized ileal digestible lysine for gilts grown in a commer- 86:2190–207. doi:10.2527/jas.2007-0408 cial finishing environment. J. Anim. Sci. 89:3587–95. doi:10.2527/ National Pork Board. 2016. Quick facts. Des Moines, IA: National jas.2010-3030 Pork Board. – [accessed August 2, 2021]. Retrieved from: https:// Soto, J. A., M. D. Tokach, S. S. Dritz, J. C. Woodworth, J. M. DeRouchey, porkgateway.org/wp-content/uploads/2015/07/quick-facts-book1. R. D. Goodband, and F. Wu. 2019. Optimal dietary standardized pdf. ileal digestible lysine and crude protein concentration for growth National Pork Board. 2020. Production Analysis Summary for U.S. and carcass performance in finishing pigs weighing greater than Pork Industry: 2017-2019. Des Moines, IA: National Pork Board. – 100 kg. J. Anim. Sci. 97:1701–1711. doi:10.1093/jas/skz052 [accessed August 2, 2021]. Retrieved from: https://library.pork.org/ Suzuki, K., T. Shibata, H. Kadowaki, H. Abe, and T. Toyoshima. 2003. media/?mediaId=4D0CDE8D-9898-44F4-A2FB321F87DE331D. Meat quality comparison of Berkshire, Duroc, and crossbred pigs NRC. 2012. Nutrient requirements of swine. 11th revised edn. National by Berkshire and Duroc. Meat Sci. 64:35–42. doi:10.1016/s0309- Academic Press, Washington, DC. 1740(02)00134-1 O’Connell, M. K., P. B. Lynch, and J. O’Doherty. 2006. The effect of Yen, J. T., J. Klindt, B. J. Kerr, F. C. Buonomo. 2005. Lysine require- dietary lysine restriction during the grower phase and subsequent ment of finishing pigs administered porcine somatotropin by dietary lysine concentration during the realimentation phase on sustained-release implant. J. Anim. Sci. 83:2789–97. the performance, carcass characteristics and nitrogen balance of doi:10.2527/2005.83122789x

Journal

Translational Animal ScienceOxford University Press

Published: Aug 12, 2022

Keywords: amino acid; economics; growth; grow-finish pig; lysine

References