Evaluation of a Colombian oregano oil (Lippia origanoides Kunth) and a novel yeast product from Pichia guilliermondii, alone or in combination, on rumen fermentation, methanogenesis and the microbiome in the rumen simulation technique

In this study, Lippia origanoides Kunth, native to the Alto Patía region in Southwest Colombia, and P ichia guilliermondii LV196, an inactivated yeast from germplasm bank of Agrosavia (Colombian Agricultural Research Corporation), alone or combined, were tested for their long-term effect on rumen fermentation methanogenesis whilst also characterising bacterial methanogen communities. Whereas essential oils act through selective inhibition microbial groups, yeasts are thought work stimulation key microbes rumen. We hypothesized that supplementation could modulate antimicrobial a high thymol-containing oregano oil, allowing more efficient feed utilization decreasing methane production. When added simulating fermentor (RUSITEC), L. Kunth at 132 µL/d had detrimental which was accompanied by reduction relative abundance protozoa fungi profound impact archaeal P. LV196 0.5 g/L, however, no parameters nutrient utilization, neither changes abundances structure communities observed. did not stimulate numbers nor activity and, consequently we test whether it have counterbalanced oil. Future studies need both investigate lower levels oil addition, but re-examine effects guillermondii and/or replace with other known biological when combined extracted Kunth.