The metabolism of short-chain fatty acids in the sheep. 3. Formic, n-valeric and some branched-chain acids

Abstract

IsoButyric, n-valeric, isovaleric and alpha-methylbutyric acids, which are known to occur in the sheep''s rumen, can be absorbed into the blood from the rumen. All these acids are metabolized to some extent when incubated with rumen epithelial tissue. Small amounts of acetate and propionate were produced from isobutyric, n-valeric and alpha-methylbutyric acids under these conditions, while isovaleric acid gave rise to acetata and possibly isobutyrate. n-Valeric and isovaleric acids increased ketone-body formation. The rate of metabolism of isovaleric acid was increased by the presence of CO2. In the absence of CO2 this acid inhibited the respiration of rumen epithelium. Liver and kidney slices also metabolized these acids, with break-down to acids of shorter chain length.