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., Frank, J.W., Usry, J.L., Allee, G.L. 2004. Evaluation of the true ileal digestible valine:lysine ratio for 13 to 32 kg barrows. Journal of Animal Science. 82(2):67.
Technical Abstract: Two experiments were conducted to determine the true ileal digestible (TID) valine:lysine (Val:Lys) ratio for 13 to 32 kg barrows. In Exp. 1, 54 individually housed barrows (PIC C-23; BW = 21.4 kg) were allotted in a randomized complete block design (RCB) with 9 replicate pens in a five-point Val:Lys titration for 14 d. In Exp. 2, 147 barrows (PIC C-23; BW = 13.5 kg) were allotted in a RCB with 7 replicate pens of 3 pigs/pen in a six-point Val:Lys titration for 21 d. Both experiments utilized a corn-soybean meal basal diet containing 0.60% L-Lysine-HCl and additional crystalline amino acids supplied as necessary to meet minimum amino acid ratios, excluding valine. The basal diet was formulated to 1.10% TID lys, 3.37 Mcal ME/kg, and a Val:Lys ratio of 55. L-Valine was added to the basal diet to achieve ratios of 60, 65, 70, and 75 in Exp. 1 and 60, 65, 70, 75, and 80 in Exp. 2. In each experiment, a control corn-soybean meal diet was formulated to contain 1.10% TID lys, 3.37 Mcal ME/kg, 0.20% L-Lysine-HCl, and a Val:Lys ratio of 74. In Exp. 2, serum samples were collected from two pigs/pen at d 0 and d 21 for determination of serum urea nitrogen (SUN). In Exp. 1, a linear increase in ADG (713, 750, 800, 796, and 785 g/d, respectively; P< 0.05) and G:F (545, 549, 572, 584, and 562 g/kg, respectively; P< 0.07) was observed with increasing Val:Lys. Breakpoint analysis revealed TID Val:Lys estimates of 65.8 and 66.2 for ADG and G:F, respectively. In Exp. 2, there was a trend for quadratic improvements in ADG (P< 0.08) and G:F (550, 557, 583, 573, 585, 572 g/kg, respectively; P< .07) with increasing Val:Lys, characterized by an improvement to a ratio of 65 and a plateau thereafter. Pigs fed the control diet did not differ from those fed 65 TID Val:Lys in Exp. 1, but did have improved G:F ratio in Exp. 2 (613 vs. 583 g/kg; P< .03). SUN levels were unaffected by dietary treatment. Using combined requirement estimates, the data suggest that a TID valine:lysine ratio of 65 appears adequate in maintaining performance for pigs from 13 to 32 kg.