Effects of Standardized Ileal Digestible Histidine:Lysine Ratio on Growth Performance of 7 to 11 Kg Pigs

• Published in: Journal of animal science Vol. 96; p. 93
• Main Authors: Cemin, H S, Tokach, M D, Vier, C M, Dritz, S S, Woodworth, J C, DeRouchey, J M, Goodband, R D, Touchette, K J
• Format: Journal Article
• Language: English
• Published: Champaign Oxford University Press 01.04.2018
• Subjects: Animal models; Animal sciences; Bayesian analysis; Corn; Deoxyribonucleic acid; Diet; DNA; Histidine; Hogs; Lysine; Mathematical models; Proteins; Whey; Whey protein
• ISSN: 0021-8812

An experiment was conducted to determine the standardized ileal digestible (SID) His:Lys ratio requirement for 7 to 11 kg pigs. A total of 360 pigs (DNA 600 x 241, initially 7.1 ± 0.31 kg BW) were fed experimental diets for 10 d with 12 replicates and 5 pigs per pen. Pens were blocked by weight and assigned in a randomized complete block design to 1 of 6 dietary treatments containing 24, 28, 32, 36, 40, or 44% SID His:Lys. Dietary SID Lys was 1.25% and all other AA met or exceeded the NRC (2012) requirement estimates. Diets were corn, spray-dried whey, and whey protein concentrate-based and treatments were formed by adding crystalline L-His at the expense of corn. Response variables ADG, ADFI, and G:F were fitted using general linear and nonlinear mixed models with heterogeneous variances and pen as the experimental unit. Competing models included quadratic polynomial, broken-line linear, and broken-line quadratic. For each response variable, the best fitting model was selected based on Bayesian Information Criterion. Increasing the His:Lys resulted in quadratic increases (P < 0.01) in ADG, ADFI, and G:F. The best fitting model for the three response variables was the broken-line linear. For ADG, the requirement was estimated at 29.7% SID His:Lys (95% CI: 27.8 to 31.6). For ADFI, the breakpoint occurred at 29.1% SID His:Lys (95% CI: 27.6 to 30.6). The maximum G:F was obtained at 29.8% SID His:Lys (95% CI: 27.6 to 32.1). In conclusion, the estimated SID His:Lys requirement for 7 to 11 kg pigs ranged from 29.1% to 29.8%.