肉牛剩余采食量相关瘤胃及粪便微生物特征比较分析.

The aim of this experiment is to investigate the composition and relative abundance of microbial species in the gastrointestinal tract of beef cattle associated with different residual feed intake (RFI), and the functional annotation and enrichment characteristics of microbial genes. Thirty cattle were selected for the 81-day feeding experiment, and at the end of the experiment, five individuals each with extreme RFI were selected for slaughter, and rumen fluid and intestinal end fecal samples were collected for macrogenome sequencing. The results showed that a total of 259 045.47 Mb valid data were obtained, 4 318 393 Scaftigs were assembled, and 7 008 053 open reading frames (ORFs) were obtained from gene prediction. Species annotation revealed no difference in the relative abundance of Top 10 species in the fecal samples between High Residual Feed Intake (HRFI) and Low Residual Feed Intake (LRFI) groups (P>0.05), and the relative abundance of Top 10 microorganisms in the rumen fluid in the LRFI group was lower than in the HRFI group; the dominant phylum in both feces and rumen fluid was the phylum Bacillus and the thick-walled phylum; the dominant genus in the feces was Bacteroides and the dominant genus in the rumen fluid was Prevotella. LefSe analysis showed a significant enrichment of Erysipelotrichia in the feces in the LRFI group (P<0.05), the most significant difference in rumen fluid was in the Methanobacterium class, and the relative abundance of this organism in the HRFI group was significantly higher than in the LRFI group (P<0.05). Functional annotation analysis using the KEGG, eggNOG and CAZy databases showed that the abundances of some functional genes of microorganisms in the gastrointestinal tract was associated with the grouping of RFI. In conclusion, the microbial structures in the rumen fluid and feces of beef cattle with different RFI varied significantly, and the Erysipelotrichia and Methanobacterium phyla may be among the potential biomarkers for differentiating feed efficiency in beef cattle. [ABSTRACT FROM AUTHOR]