Analysis of 4-methyloctanoic acid and other medium chain-length fatty acid constituents of ovine tissue lipids

Medium chain-length (C6−C9) fatty acids in depot, intramuscular, kidney, and liver lipids from pasture-fed sheep and subcutaneous and intramuscular lipids from barley-fed sheep were analyzed with emphasis on the 4-methyloctanoic acid (hircinoic acid) content. Within individual animals, the level of hircinoic acid in the subcutaneous fat was usually higher than that either in the deeper depot fats or in the intramuscular fat. Variation of hircinoic acid levels between animals was greatest in the subcutaneous fat and least in the perinephric fat. There were usually higher levels of both branched and odd carbon chain fatty acids in the lipids of barley-fed sheep than in the corresponding lipids of pasture-fed sheep.