Amino acid maintenance requirements of young women and of adult rats fed different dietary amino acid patterns.

Adult rats were fed isonitrogenous diets (5% protein equivalent) providing indispensable amino acids either in the whole-egg protein pattern or in the adult rat maintenance pattern of Smith and Johnson (S & J. Brit. J. Nutr. 21:17, 1967). In two separate experiments the threonine and the methionine (total sulfur amino acid) requirements were assessed. Similar responses were obtained with rats on the threonine experiment independent of the pattern of indispensable amino acids fed. In the methionine experiment the rats fed the S & J pattern showed a lower need for this amino acid than the rats fed the egg pattern. When the latter group was switched to the S & J pattern, they too required less methionine. In the experiment with college students (female) fed 7 g of nitrogen/subject per day, the lysine requirement on the whole-egg pattern was compared to the requirement on a pattern equal to twice the previously published requirements for young women. No evidence was obtained over the relatively short experimental period that the lysine requirement differed substantially with change in the pattern of indispensable amino acids.