Impairment of rumen biohydrogenation and bacteria of the Butyrivibrio group in the rumen of goats through a 20:5 n-3 (EPA) rich supplement.

Abstract

Marine products can inhibit biohydrogenation in the rumen, but the mechanism is not clear. This study investigated a 20:5 n-3 rich supplement effects on rumen biohydrogenation, microbial change and fermentation characteristics in goats. The supplementation decreased 18:0 proportions in rumen fatty acids (P < 0.001), while it increased cis-9, trans-11 conjugated linoleic acid (CLA) (P < 0.001) and trans-10, cis-12 CLA proportions (P < 0.001). The supplement reduced the number of Butyrivibrio spp. and B. proteoclasticus (P < 0.01). Denaturing gradient gel electrophoresis redundancy analysis indicated that some species, mainly from the rumen of goats receiving the 2.5 and 5.0 g d(-1) supplement, were positively correlated with cis-9, trans-11 CLA proportions; some species, mainly from the rumen of control goats, were positively correlated with 18:0 proportions. The supplement reduced the NH3 -N concentrations and acetate molar proportions in the rumen (P < 0.05), but increased propionate and butyrate molar proportions (P < 0.01), and had no effect on total volatile fatty acid concentration. The supplement rich in 20:5 n-3 reduced the biohydrogenation of 18-carbon unsaturated fatty acids with a significant reduction of the 18:0 proportion and this was coupled with the suppression of the abundance of biohydrogenating bacteria and unknown bacteria.