Accumulation of trans C _18:1 Fatty Acids in the Rumen after Dietary Algal Supplementation Is Associated with Changes in the Butyrivibrio Community

Abstract

Optimization of the fatty acid composition of ruminant milk and meat is desirable. Dietary supplementation of algae was previously shown to inhibit rumen biohydrogenation, resulting in an altered milk fatty acid profile. Bacteria involved in biohydrogenation belong to the Butyrivibrio group. This study was aimed at relating accumulation of biohydrogenation intermediates with shifts in Butyrivibrio spp. in the rumen of dairy cows. Therefore, an experiment was performed with three rumen-fistulated dairy cows receiving a concentrate containing algae (9.35 g/kg total dry matter [DM] intake) for 20 days. Supplementation of the diet with algae inhibited biohydrogenation of C 18:2 omega 6 (n-6) and C 18:3 n-3, resulting in increased concentrations of biohydrogenation intermediates, whereas C 18:0 decreased. Addition of algae increased ruminal C 18:1 trans fatty acid concentrations, mainly due to 6-and 20-fold increases in C 18:1 trans 11 (t11) and C 18:1 t10. The number of ciliates (5.37 log copies/g rumen digesta) and the composition of the ciliate community were unaffected by dietary algae. In contrast, supplementation of the diet with algae changed the composition of the bacterial community. Primers for the Butyrivibrio group, including the genera Butyrivibrio and Pseudobutyrivibrio, were specifically designed. Denaturing gradient gel electrophoresis showed community changes upon addition of algae without affecting the total amount of Butyrivibrio bacteria (7.06 log copies/g rumen DM). Clone libraries showed that algae affected noncultivated species, which cluster taxonomically between the genera Butyrivibrio and Pseudobutyrivibrio and might play a role in biohydrogenation. In addition, 20% of the clones from a randomly selected rumen sample were related to the C 18:0 -producing branch, although the associated C 18:0 concentration decreased through supplementation of the diet with algae.

Role of the protozoan Isotricha prostoma, liquid-, and solid-associated bacteria in rumen biohydrogenation of linoleic acid

“…The SAB fraction produced considerable amounts of C18:0 and 6 SAB clones were closely associated with the C18:0-producing branch whereas 32 SAB clones were positioned on different sub-clusters between both genera (Figure 1). Similar results were obtained in a previous experiment with dairy cows supplemented with docosahexaenoic acid-enriched algae, which dramatically decreased ruminal C18:0 production, although 20% of the clones remained clustered in close relationship with the C18:0-producing branch (Boeckaert et al, 2008).…”

“…Lipid extraction followed the method of Folch et al (1957) with some adaptations as described by Chow et al (2004). Methylation of fatty acids and subsequent identification of fatty acid methyl esters were performed as described in Boeckaert et al (2008).…”

“…A PCR to amplify a fragment of the 16S rRNA gene of the Butyrivibrio group was performed following Boeckaert et al (2008). The amplified PCR product of one LAB, SAB and B sample was cloned using a TOPO-TA cloning kit (Invitrogen, Carlsbad, CA, USA) according to the manufacturer's instructions in order to create a clone library.…”

Effect of grain type and processing method on rumen fermentation and milk rumenic acid production

“…Tajima et al (2001) quantified changes of up to 10 different rumen bacteria in cows with a dietary switch from hay to grain using real-time PCR technique. Boeckaert et al (2008) showed that algae feeding changed the rumen FA profile and these changes were associated with changes in the bacterial community. But the challenge remains in identifying the t10-18:1 producing bacterial species under these modified rumen conditions.…”

Quantitative analysis of ruminal bacterial populations involved in lipid metabolism in dairy cows fed different vegetable oils

“…Also, Butyrivibrio proteoclasticus has been reported to be the principal rumen bacteria involved in biohydrogenation of C18:1 FA (Boeckaert et al, 2008). On the other hand, P. bryantii has been described as a ruminal bacterium that is involved in oligosaccharolytic and xylanolytic activities (Tajima et al, 2001) and also Prevotella spp.…”