The rumen microbiota comprises a vast range of bacterial taxa, which may affect the production of high-quality meat in Japanese Black cattle. The aim of this study was to identify core rumen microbiota in rumen fluid samples collected from 74 Japanese Black cattle raised under different dietary conditions using 16S rRNA gene amplicon sequencing. In the rumen of fattening Japanese Black cattle, 10 bacterial taxa, showing >1% average relative abundance and >95% prevalence, irrespective of the dietary conditions and the fattening periods, were identified as the core rumen bacterial taxa, which accounted for approximately 80% of the rumen microbiota in Japanese Black cattle. Additionally, population dynamics of the core rumen bacterial taxa revealed two distinct patterns: Prevotella spp. and unclassified Bacteroidales decreased in the mid-fattening period, whereas unclassified Clostridiales, unclassified Ruminococcaceae, Ruminococcus spp., and unclassified Christensenellaceae increased during the same period. Therefore, the present study reports the wide distribution of the core rumen bacterial taxa in Japanese Black cattle, and the complementary nature of the population dynamics of these core taxa, which may ensure stable rumen fermentation during the fattening period.

中文翻译：

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日本黑牛育肥期核心瘤胃细菌类群的鉴定及其种群动态

瘤胃微生物群包含范围广泛的细菌类群，这可能会影响日本黑牛优质肉的生产。本研究的目的是使用 16S rRNA 基因扩增子测序鉴定从 74 头在不同饮食条件下饲养的日本黑牛收集的瘤胃液样本中的核心瘤胃微生物群。在育肥日本黑牛的瘤胃中，10 个细菌类群被确定为核心瘤胃细菌类群，平均相对丰度 >1%，流行率 >95%，与日粮条件和育肥期无关，约占 80日本黑牛瘤胃微生物群的百分比。此外，核心瘤胃细菌类群的种群动态揭示了两种不同的模式：属 和未分类的拟杆菌门在育肥中期减少，而未分类的梭菌目、未分类的瘤胃球菌科、瘤胃球菌属和未分类的克里斯滕氏菌科在同一时期增加。因此，本研究报告了日本黑牛核心瘤胃细菌类群的广泛分布，以及这些核心类群的种群动态的互补性，这可能确保育肥期间稳定的瘤胃发酵。