ALMQUIST and Mecchi (1941) re-•**• ported that the L-tryptophan requirement for optimum growth of chicks was 0.5 percent of the diet. Results obtained by Grau and Almquist (1944) indicated that the L-tryptophan requirement was 0.25 percent of the ration, and that D-tryptophan was not utilized by the chick. Wilkening and associates (1947) fed purified diets to chicks in which the major sources of protein were 12 percent of oxidized casein and 10 percent of gelatin supplemented with cystine and methionine. Using this ration with graded levels of tryptophan, the L-tryptophan requirement was reported to be 0.18 percent of the diet. observed 17 to 40 percent utilization of D-tryptophan by the chick. The tryptophan requirement for poults was reported by Bird (1950) to be 0.28 percent of the diet for optimum growth and feed efficiency to three weeks of age. It was concluded that the poults were able to utilize 38.2 percent of the D-tryptophan.Tryptophan deficiency in the chick has been described by Brown et al. (1948). Gross symptoms included emaciation, retarded comb growth and a rapid re-
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.