Journal of Animal Science, Vol 76, Issue 4 1075-1080, Copyright © 1998 by American Society of Animal Science

JOURNAL ARTICLE

Influence of dietary lysine on growth performance and carcass characteristics of late-finishing gilts

J. A. Loughmiller, J. L. Nelssen, R. D. Goodband, M. D. Tokach, E. C. Titgemeyer and I. H. Kim
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-0201, USA.

We conducted two experiments evaluating the lysine requirement of 91- to 113-kg gilts. Gilts (PIC L326 x C-22) with initial body weights of 42 (Exp. 1) or 39 kg (Exp. 2) were blocked by weight in a randomized complete block design. Experiment 1 included 105 gilts, with seven gilts per pen and five replications (pens) per treatment. Experiment 2 included 125 gilts, with eight gilts per pen and four replications (pens) per treatment. Gilts were fed a corn-soybean meal diet (no crystalline lysine) containing 1.0% total lysine from 39 to 68 kg and .80% total lysine from 68 to 91 kg. In Exp. 1, when the average weight of gilts within a block reached 91 kg, gilts were fed corn-soybean meal diets containing .40, .55, or .70% total lysine. Increasing dietary lysine increased (linear, P < .05) ADG, daily lysine intake (11.3, 15.1, and 19.8 g/d), gain/feed, plasma urea N, and carcass lean percentage but decreased 10th rib fat depth. Because of the linear responses in Exp. 1, Exp. 2 was conducted with corn-soybean meal diets containing .60, .70, .80, or .90% total lysine. Increasing total dietary lysine had no effect on ADG, gain/feed, 10th rib fat depth, or carcass lean percentage (P > .10). Daily lysine intake increased (linear, P < .01) with increasing dietary lysine (18.1, 21.1, 23.9, 26.5 g/d). Based on these results, the total dietary lysine requirement for 91- to 113-kg gilts is approximately .60% total lysine, which corresponds to approximately 18 g/d lysine intake.