The bacterial and archaeal community structures and methanogenic potential of the cecal microbiota of goats fed with hay and high-grain diets

The cecum plays an important role in the feed fermentation of ruminants. However, information is very limited regarding the cecal microbiota and their methane production. In the present study, the cecal content from twelve local Chinese goats, fed with either a hay diet (0% grain) or a high-grain diet (71.5% grain), were used to investigate the bacterial and archaeal community and their methanogenic potential. Microbial community analysis was determined using high-throughput sequencing of 16S rRNA genes and real-time PCR, and the methanogenesis potential was assessed by in vitro fermentation with ground corn or hay as substrates. Compared with the hay group, the high-grain diet significantly increased the length and weight of the cecum, the proportions of starch and crude protein, the concentrations of volatile fatty acids and ammonia nitrogen, but decreased the pH values (P?P?Bifidobacterium, Prevotella, and Treponema were significantly increased in the high-grain group (P?Akkermansia, Oscillospira, and Coprococcus were significantly decreased (P?Methanosphaera stadtmanae was significantly increased in the high-grain group (P?Methanosphaera sp. ISO3-F5 was significantly decreased (P?P?P?