Altering Methane Emission, Fatty Acid Composition, and Microbial Profile during In Vitro Ruminant Fermentation by Manipulating Dietary Fatty Acid Ratios

This study evaluated the effects of different dietary n-6/n-3 polyunsaturated fatty acid (PUFA) ratios on in vitro ruminant fermentation. Methane production, composition, and microbial profiles were compared after fermentation rumen fluid collected from cows that had been fed isoenergetic isoproteic experimental diets at three ratios: 3.04 (HN6, high n-6 source), 2.03 (MN6, medium 0.8 (LN6, low source). The fermented pH total volatile (VFA) levels significantly decreased (p < 0.05) HN6 group as with those MN6 LN6 groups. Additionally, produced a lower proportion methane than during groups increased C18:2n6 C18:3n3 fluid, respectively, group. Chao 1 diversity index value was observed species richness reduced relative abundances Lachnospiraceae UCG-006 Selenomonas resulted VFA (i.e., acetate, propionate, butyrate, VFA) Furthermore, n-3 PUFAs toxic to Butyrivibrio_2 growth, resulting incomplete biohydrogenation. Taken together, findings suggest supplementation high-forage could reduce emissions, whereas both concentration are reduced.