The Retention of Essential Amino Acids by the Growing Chick , ,

Abstract

The percentage retentions of essential amino acids were determined for the growing chick when fed a chick starter ration (ration A) whose protein sources were largely of plant origin, and ration B, containing high percentages of animal proteins but partially deficient in certain essential amino acids. On ration A, 24 to 43% of the essential amino acids consumed was retained by the body, 11 to 21% was excreted, and 36 to 58% was unaccounted for and considered to have been catabolized. Corresponding values for ration B were 39 to 71%, 9 to 15%, and 20 to 51%. Of the total nitrogen consumed, 56% was retained, 38% excreted and 6% unaccounted for. There was a marked similarity in the patterns of the essential amino acids in the total protein of the chick carcasses and the rations. Also, the patterns for the two groups of chicks were essentially the same.