Sulfur Amino Acid Requirements for Growth of Mice Fed Two Levels of Nitrogen

Abstract

A casein-amino acid diet was developed that will sustain growth in the mouse equivalent to that obtained with an isonitrogenous, cystine-supplemented casein diet. The casein-amino acid diet was used to determine the total sulfur amino acid requirement for maximal growth in the weanling mouse at two nitrogen levels, 2.5 and 1.5% of the diet. The estimated requirement for total sulfur amino acids at the 2.5 and 1.5% levels of nitrogen was 0.53 and 0.20% of the diet, respectively. Data were presented which indicate that at the 2.5% nitrogen level cystine can meet over one-half of the total sulfur amino acid requirement.