Effects of the inclusion of flaxseed and quercetin in the diet of fattening lambs on ruminal microbiota,in vitrofermentation and biohydrogenation of fatty acids

Abstract

SUMMARYThirty-two lambs (n = 8 per treatment) were fed a total mixed ration (TMR) formulated either with palm oil (CTRL; 34 g palm oil/kg TMR) or flaxseed (FS) (85 g FS/kg TMR) alone or enriched with quercetin (QCT, 34 g palm oil plus 2 g QCT/kg TMR; FS-QCT, 85 g FS plus 2 g QCT/kg TMR). The animals were slaughtered after being fed for at least 5 weeks with the experimental diets and samples of ruminal contents and ruminal liquid were collected for quantitative real-time polymerase chain reaction analyses of ruminal microbial species and fatty acid profile orin vitrofermentation, respectively. Results demonstrated thatButyrivibriovaccenic acid (VA) andButyrivibriostearic acid (SA) producing bacteria copy numbers were decreased when FS was added to the diet of fattening lambs, which seemed to be in agreement with numerically (but not significantly) lower values for gas production, methane production and butyric acid duringin vitroincubation. Ciliate protozoa were significantly enhanced by QCT, which was in accordance with numerically (but not significantly) higher values forin vitromethane production. Moreover, the modifications observed in ruminal microbial populations (Butyrivibrioand ciliate protozoa) when FS and QCT were included together (but not separately) in the diet of fattening lambs were probably related to a trend towards significantly higher values of rumenic acid (RA) in ruminal content. In conclusion, when FS and QCT were administered together in the diet of fattening lambs quantitative changes in the ruminal microbiota were observed, which might have promoted an increment of RA concentration in ruminal contents.