The incorporation of long-chain fatty acids into lipids by rumen bacteria and the effect on biohydrogenation

Abstract

16–30% of the 14C recovered from rumen contents and mixed rumen bacteria following 2.5–4.0-h incubations with [1- 14C]linolenic acid was in ester form. The 14C-labelled fatty acids of these acyl lipids were, in general, much less saturated than the corresponding 14C-labelled free fatty acids which supports an earlier conclusion that a free carboxyl group is required for the biohydrogenation of unsaturated fatty acids. Bacterial preparations which were virtually free from protozoa incorporated free fatty acid into sterol ester and polar lipids. The extent of biohydrogenation in the rumen could be affected by the utilization of free fatty acids released from dietary lipid by lipolysis.