Influence of Nonessential L-Amino Acids on Growth of Rats Fed High Levels of Essential L-Amino Acids

Abstract
Summary Weanling rats were fed purified L-amino acid diets containing high levels of essential L-amino acids (EAA) to determine the effect of nonessential amino acids (NEAA) on growth. Observations were made also on the liver composition and plasma amino nitrogen (PAN) levels. A diet containing high levels of only the EAA resulted in poor growth (3.8 g/day), as compared with a casein diet (5.6 g/day). However, when six NEAA were added to this amino acid diet, growth rate (5.2 g/day) and food efficiency were significantly improved. Proline added singly caused a significant growth improvement; on the other hand, glycine, glutamic acid, aspartic acid, alanine, serine, or urea did not significantly improve the growth rate.