EFFECTS OF INORGANIC SULFATE SUPPLEMENTS ON THE GROWTH OF RATS FED SULFUR AMINO ACID-DEFICIENT DIETS

Abstract

Rats were fed sulfur amino acid-deficient diets supplemented with inorganic sulfate to test whether sulfate spared sulfur amino acids for growth. The dietary protein sources used were lupin kernels, alfalfa leaf protein concentrate, commercial casein, or purified casein; 10% protein diets were supplemented with sodium sulfate (1.5 g/kg) and/or various levels of DL-methionine. Sulfate did not improve weight gain or protein efficiency ratio when added to diets containing lupin kernels, alfalfa leaf protein concentrate, or commercial casein. The lack of response was probably due to the relatively high intrinsic non-protein sulfur or inorganic sulfate contents of the diets. When the intrinsic sulfate level was reduced to 0.003% as in the purified casein diet, added sulfate significantly improved weight gain and protein efficiency ratio.