Efecto del DHA sobre la biohidrogenación ruminal in vitro de ácidos grasos de 18 carbonos: comparación en vacas y ovejas

Despite the established differences in ruminal biohydrogenation (BH) between cows and small ruminants fed vegetable oils, it has been suggested that differences would be less clear when it comes to marine lipids (rich in very long-chain n-3 PUFA). Thus, this study was conducted simultaneously in bovine and ovine to compare the in vitro BH of C18 fatty acids (FA) to 22:6n-3 (DHA). Batch cultures of rumen microorganisms were carried out using cannulated cows and ewes as inocula donors, and DHA was added at a dose of 2% incubated DM. Although DHA had a similar impact on 18:0 accumulation in cows and sheep, greater increases in t11-18:1 concentration were found in bovine, whereas alternative BH pathways that lead to the accumulation of minor trans 18:1 isomers were further promoted in ewes. These relevant specificities may probably derive from interspecies differences in rumen microbial composition. The saturation of cis 18:1 and 18:2 isomers was also inhibited in both species. Changes in oxo-FA concentrations suggested that ruminal hydration (an alternative metabolic pathway to BH) was affected to a different extent in cows and ewes.