Submitted to: Journal of Animal Science
Publication Type: Abstract only
Publication Acceptance Date: 3/15/2004
Publication Date: 3/15/2004
Citation: Kendall, D.C., Kerr, B.J., Fent, R.W., Fu, S.X., Usry, J.L., Allee, G.L. 2004. Determination of the true ileal digestible isoleucine requirment for 90 kg barrows. Journal of Animal Science. 82(2):67. Interpretive Summary:
Technical Abstract: 21 d experiment was conducted to determine the true ileal digestible (TID) isoleucine requirement for 91 to 116 kg barrows (n=170, PIC C-23). Pigs were allotted by weight in a randomized complete block design and fed one of five dietary treatments with five replicates of six or seven pigs per pen. A four-point titration curve was constructed with a basal diet containing corn and 5.0% blood cells. The basal diet contained 0.25% TID Ile, 0.63% TID lys, and 3.47 Mcal ME/kg. The 0.63% TID lys was considered above the requirement for this genotype. Additional amino acids were supplied from crystalline sources to meet minimum amino acid ratios. L-Ile was added at the expense of cornstarch, creating the three other TID Ile levels (0.30, 0.35, and 0.40% TID Ile). A control corn-soybean meal diet was formulated to contain 0.63% TID lys, 3.47 Mcal ME/kg, and 0.47% TID Ile. There were linear improvements (P< .001) and quadratic trends in final BW (P< .07) and ADG (0.662, 0.918, 1.15, and 1.21 kg/day, respectively; P< .06). A linear increase in ADFI (2.62, 3.01, 3.55, and 3.62 kg/day, respectively; P< 0.001) was observed with increasing TID Ile, resulting in a quadratic improvement in G:F with increasing TID Ile (0.251, 0.303, 0.324, 0.335, respectively; P< .01). Pigs fed the control diet had similar ADG (1.19 vs. 1.21) and G:F (0.335 vs. 0.335) compared to pigs fed the 0.40% TID Ile diet. One-slope breakpoint analysis of ADG and G:F yielded TID Ile requirement estimates of 0.361 and 0.357, respectively. This experiment demonstrates that the TID Ile requirement for 91 to 117 kg barrows is near 0.36% TID Ile. It also illustrates that pig performance is comparable when diets are formulated with blood cells, provided additional Ile is supplied.