Glycine Need of the Chick Fed Casein Diets and the Glycine, Arginine, Methionine and Creatine Interrelationships

Abstract

The arginine-glycine interrelationship on a casein-glucose diet of approximately 20% of crude protein was studied in factorial experiments. These two amino acids, added either singly or in combination, were demonstrated to increase growth over that observed in chicks fed the unsupplemented basal diet. Chick growth continued to increase with increments of glycine at arginine levels in excess of the arginine requirement established for this diet and the favorable effect of glycine was shown to be independent of the arginine concentration in the diet. The glycine-creatine and glycine-methionine interrelationships were examined on the casein-glucose basal diet in the presence of adequate arginine. Chick growth increased significantly when 0.5% of creatine hydrate was added to the diet at all levels of glycine. Chick growth increased progressively with each increment of glycine at all levels of creatine and was shown to be independent of the creatine concentration in the diet. The response to supplemental DL-methionine (0.2 to 0.4%) was shown to be dependent on the presence of supplemental glycine. Supplemental glycine alleviated the growth depression induced by 0.8% of supplemental DL-methionine.