The Effects of Different Isomers of Methionine on Growth of Chicks Fed Amino Acid Diets

Abstract

BOTH d- and l-methionine are effectively utilized by rats (Wretlind and Rose, 1950), by humans (Rose et al., 1950, 1955), and by dogs (Stekol, 1935). Research carried out on chicks has brought about varying results. Grau and Almquist (1943) were among the earliest to demonstrate full utilization of both d-and l-isomers of methionine in chicks. Fell et al. (1959) used a semipurified diet in studies of the utilization of d- and l-amino acids. He showed that both isomers of methionine were effective in promoting growth. The d- forms of essential amino acids appear to be capable of serving as the major source of nitrogen for the chick’s manufacture of non-essential amino acids (Featherston et al., 1962). Full utilization of d-methionine was observed in adult roosters when all three forms were fed in nitrogen balance studies (Leveille et al., 1960). Because most of the work on amino acids with chicks…