Sequence in which Indispensable and Dispensable Amino Acids Become Limiting for Growth of Rats Fed Diets Low in Fibrin

Abstract

The results of growth experiments indicate that in diets containing 6% of fibrin as the only source of protein leucine, isoleucine, valine and histidine are all equally the most limiting amino acids for the growth of the rat; methionine and phenylalanine are equally next limiting; lysine is the third limiting amino acid and threonine, arginine and tryptophan are least limiting. Diets containing 6% of fibrin supplemented with a mixture of the indispensable amino acids to satisfy the accepted amino acid requirements of the rat do not support optimal growth. Addition of a mixture of dispensable amino acids containing glutamic acid, glycine, aspartic acid and alanine or addition of glutamic acid alone stimulates growth considerably.