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 microbiome in the Rumen Simulation Technique. 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 microbiome in the Rumen Simulation Technique

In this study, Lippia origanoides Kunth, native of the Patía region in Southwest Colombia, and Pichia guilliermondii LV196, an inactivated yeast from the germplasm bank of Agrosavia (Colombian Agricultural Research Corporation), alone or combined, were tested for their long-term effect on rumen fermentation and methanogenesis whilst also characterising their effect on bacterial and methanogen communities. When added to a rumen simulating fermentor (RUSITEC), Lippia origanoides Kunth at 132 microliters/d had a detrimental effect on rumen fermentation which was accompanied by a reduction in the relative abundance of protozoa and fungi and a profound impact on the bacterial and archaeal communities. Pichia guilliermondii LV196 at 0.5 g/L, however, had no effect on fermentation parameters or nutrient utilization, and neither changes in microbial abundances or in the structure of bacterial and archaeal communities were observed. Further studies with lower doses of the essential oil and higher doses of the yeast product are needed to explore the potential of these feed additives, either alone or combined, to enhance productivity whereas reducing methane emissions.

本研究以哥伦比亚西南部帕蒂亚地区原生的牛至叶过江藤（Lippia origanoides Kunth），以及源自哥伦比亚农业研究公司（Agrosavia）种质库的灭活酵母季也蒙毕赤酵母（Pichia guilliermondii LV196）为受试材料，分别设置单独施用与联合施用两组处理，探究其对瘤胃发酵与甲烷生成的长期影响，并同步表征其对细菌和产甲烷古菌群落的调控作用。将受试材料添加至瘤胃模拟发酵罐（RUSITEC）后发现，剂量为132微升/天的牛至叶过江藤会对瘤胃发酵产生不利影响，伴随瘤胃中原生动物与真菌相对丰度的降低，同时对细菌和古菌群落结构造成显著扰动。然而，浓度为0.5 g/L的季也蒙毕赤酵母LV196对发酵参数及养分利用无显著影响，未观察到微生物丰度或细菌、古菌群落结构发生明显变化。后续需开展更低剂量该精油、更高剂量该酵母制剂的相关试验，以探究这两类饲料添加剂单独或联合使用，在提升生产性能同时降低甲烷排放的应用潜力。