The Arginine Requirement of Chicks in Relation to Diet Composition

IT IS becoming increasingly apparent that the amino acid requirement of the chick, expressed as a percentage of the diet, bears an inverse relationship to the utilizable energy content of the ration. Thus the growth promoting ability of highly refined diets containing suboptimal percentage levels of lysine, Williams and Grau (1956), and either tryptophan or arginine, Griminger et al. (1957), was materially improved by decreasing their content of digestible energy. The former group used a 15 percent protein sesame meal diet while Griminger and co-workers employed a 20 percent protein casein ration which has subsequently been shown to be severely deficient in total protein, Scott et al. (1957), It is conceivable, therefore, that the growth improvement resulting from the substitution of cellulose for cerelose reflects the increased intake of both protein and the limiting amino acid under investigation. It seemed desirable, therefore, to re-examine the problem under conditions where the . . .