Efficacy of a lysine-tryptophan blend for growth of chicks.

Two chick experiments were conducted to compare the growth-promoting efficacy as well as the toxicity of a new source of L-tryptophan and L-lysine, Tryptosine (16.1% tryptophan, 56.3% lysine). A corn-feather meal-soybean meal basal diet was made singly deficient in either lysine or tryptophan, and graded doses of lysine or tryptophan from either Tryptosine or feed-grade sources of lysine and tryptophan were supplemented. Linear (P < .01) weight gain responses occurred, and responses to lysine or tryptophan in Tryptosine were similar to those obtained with equal doses of lysine or tryptophan provided by feed-grade sources of L-lysine.HCI or L-tryptophan. The toxicity trial involved additions of 1, 2, or 4% lysine with .29, .58, or 1.16% tryptophan to a lysine- and tryptophan-adequate corn-soybean meal diet. Both amino acids were provided as either Tryptosine or as feed-grade sources of lysine and tryptophan. Weight gain and feed intake were reduced in a linear fashion (P < .01) as levels of the two excess amino acids increased. The decreases caused by Tryptosine were similar to those caused by equivalent levels of excess feed-grade lysine and tryptophan.

Sorghum amino acid-supplemented diets for the 50- to 100-kilogram pig.

Three experiments were conducted to evaluate lysine (Lys), threonine (Thr), methionine (Met), tryptophan (Trp), and nonessential N (+N) supplementation of all sorghum grain (S) diets on growth and carcass characteristics of 50- to 100-kg pigs. In Exp. 1, four replicate pens of four pigs each were fed: 1) sorghum-soybean meal positive control (S-SBM); 2) S + Lys + Thr + Met + Trp to equal the amino acid concentrations in S-SBM (LTMT); 3) Diet 2 + N (LTMT+N); and 4) S negative control. Compared with pigs fed S-SBM, pigs fed LTMT or LTMT+N had reduced (P < .05) ADG, ADFI, serum urea N (SUN), pancreas weight, LMA, and percentage of muscling (PM) but higher dressing percentage (DP) and similar 10th rib fat thickness (TRF). Apparent N digestibility was lower (P < .05) in pigs fed LTMT than in pigs fed LTMT+N or S-SBM. In Exp. 2, two replicate pens of four pigs each were fed: 1) S-SBM; 2) S + Lys + Thr (LT); 3) S + Lys + Thr + Met (LTM); 4) S + Lys + Thr + Trp (LTT); 5) LTMT; 6 to 9) as 2 to 5 +N; and 10) S negative control. Compared with pigs fed S-SBM, pigs fed S, LT, LT+N, and LTM+N had lower (P < .05) ADG. Daily gain of pigs fed LTM, LTT, LTMT, LTT+N, or LTMT+N was not different (P > .10) from pigs fed S-SBM.(ABSTRACT TRUNCATED AT 250 WORDS)