Degradation of protein in the rumen of the sheep. 1. Some volatile fatty acids, including branched-chain isomers, found in vivo

Abstract

Using the gas-liquid partition chromatogram of James and Martin (ibid. 50: 679. 1952) it was found that branched-chain lower fatty acids occur in the rumen of the sheep on a variety of diets. A significant proportion of the C4 acids was isobutyric acid, and branched-chain isomers often made up the greater part of the C5 acids. Cg acids were present only in small amts. The concns. of ammonia and of the various volatile fatty acids in the rumen were detd. at different times after feeding. Increased ammonia concn. was correlated with increased concns. of isobutyric acid and of the C5 acids, which are, therefore, considered to arise from microbial attack on protein in the rumen.