Could Quinella-like microorganisms be involved in the formation of saturated oxygenated fatty acids in the rumen of lactating sheep fed diets containing sunflower oil and marine algae?

Abstract

Dietary supplements of sunflower oil (SO) in combination with marine lipids (fish oil or marine algae; MA) are known to increase the concentration of potentially beneficial bioactive lipids, including cis-9, trans-11 conjugated linoleic acid in ovine milk (Toral et al. 2010a). Changes in milk fat composition are related to diet-induced alteratios in ruminal biohydrogenation (BH) of unsaturated fatty acids (FA) and associated ruminal microbiota. Inclusion of SO with fish oil also promotes the accumulation of oxygenated 18-carbon saturated FA in ruminal digesta in sheep (Toral et al. 2010b). However, the bacterial species responsible for the formation and accumulation of keto and hydroxyl FA in the rumen are not well characterised. In the current study, ruminal fluid from lactating ewes fed a diet supplemented with SO plus incremental amounts of MA was used to investigate the association between the formation and accumulation of 18-caron saturated keto FA and the variations in the rumen bacterial community.