Ruminants burp massive amounts of methane into the atmosphere and significantly contribute to the deposition of greenhouse gases and the consequent global warming. It is therefore urgent to devise strategies to mitigate ruminant’s methane emissions to alleviate climate change. Ruminal methanogenesis is accomplished by a series of methanogen archaea in the phylum Euryarchaeota, which piggyback into carbohydrate fermentation by utilizing residual hydrogen to produce methane. Abundance of methanogens, therefore, is expected to affect methane production. Furthermore, availability of hydrogen produced by cellulolytic bacteria acting upstream of methanogens is a rate-limiting factor for methane production. The aim of our study was to identify microbes associated with the production of methane which would constitute the basis for the design of mitigation strategies. Moderate differences in the abundance of methanogens were observed between groups. In addition, we present three lines of evidence suggesting an apparent higher abundance of a consortium of Prevotella species in animals with lower methane emissions. First, taxonomic classification revealed increased abundance of at least 29 species of Prevotella. Second, metagenome assembly identified increased abundance of Prevotella ruminicola and another species of Prevotella. Third, metabolic profiling of predicted proteins uncovered 25 enzymes with homology to Prevotella proteins more abundant in the low methane emissions group. We propose that higher abundance of ruminal Prevotella increases the production of propionic acid and, in doing so, reduces the amount of hydrogen available for methanogenesis. However, further experimentation is required to ascertain the role of Prevotella on methane production and its potential to act as a methane production mitigator.

中文翻译：

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较低的甲烷排放量与哥伦比亚水牛队列中瘤胃普雷沃氏菌的丰度较高有关

反刍动物将大量甲烷排放到大气中，并显着导致温室气体的沉积和随之而来的全球变暖。因此，迫切需要制定策略来减少反刍动物的甲烷排放以缓解气候变化。瘤胃产甲烷是由 Euryarchaeota 门中的一系列产甲烷古菌完成的，它们通过利用残留的氢产生甲烷来搭载碳水化合物发酵。因此，大量产甲烷菌预计会影响甲烷产量。此外，在产甲烷菌上游起作用的纤维素分解细菌产生的氢气的可用性是甲烷产生的限速因素。我们研究的目的是确定与甲烷生产相关的微生物，这将构成缓解策略设计的基础。在各组之间观察到产甲烷菌丰度的中等差异。此外，我们提出了三条证据，表明在甲烷排放量较低的动物中，普氏菌群的丰度明显更高。首先，分类学分类显示至少 29 种普氏菌的丰度增加。其次，宏基因组组装确定了普氏菌和另一种普氏菌的丰度增加。第三，预测蛋白质的代谢分析发现了与低甲烷排放组中更丰富的普氏菌蛋白同源的 25 种酶。我们建议瘤胃普雷沃氏菌的丰度增加会增加丙酸的产量，从而减少可用于产甲烷的氢气量。然而，需要进一步的实验来确定普雷沃氏菌对甲烷生产的作用及其作为甲烷生产缓解剂的潜力。