Dietary and Defaunation Effects upon Plasma Amino Acid Concentrations in Sheep

Abstract

When 2 rations were each fed to a group of 3 sheep fed twice daily, plasma amino acid concentrations were greater than pre-feeding concentrations with an 8.1% protein ration, whereas the converse was true for a 12.5% protein ration. In a second experiment, substitution of a concentrate ration for a roughage ration on the sample day only, resulted in lower plasma amino acid concentrations. In a third experiment, the infusion of a starch-glucose mixture into the rumen at the usual feeding time resulted in reduced plasma amino acid concentrations. Infusion at 1.5% of the metabolic weight (B.W.^0.75) gave a greater reduction than did infusion at 1.2% of the metabolic body weight (B.W.^0.75). Defaunated lambs showed higher concentrations of plasma amino acids and a greater decrease in concentration following starch glucose infusion than did comparable faunated animals.