EFFICACY OF A LYSINE-TRYPTOPHAN BLEND FOR GROWTH OF CHICKS

Two chick experiments were conducted to compare the growth-promoting e fficacy as well as the toxicity of a new source of L-tryptophan and L- lysine, Tryptosine(R) (16.1% tryptophan, 56.3% lysine). A corn-feather meal-soybean meal basal diet was made singly deficient in either lysi ne or tryptophan, and graded doses of lysine or tryptophan from either Tryptosine(R) or feed-grade sources of lysine and tryptophan were Sup plemented. Linear (P < .01) weight gain responses occurred, and respon ses to lysine or tryptophan in Tryptosine(R) were similar to those obt ained with equal doses of lysine or tryptophan provided by feed-grade sources of L-lysine HCl or L-tryptophan. The toxicity trial involved a dditions 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 ac ids were provided as either Tryptosine or as feed-grade sources of lys ine and tryptophan. Weight gain and feed intake were reduced in a line ar fashion (P < .01) as levels of the two excess amino acids increased . The decreases caused by Tryptosine were similar to those caused by e quivalent levels of excess feed-grade lysine and tryptophan.