Differences of rumen microorganisms between high and low residual feed intake of Tan sheep

Residual feed intake is a measure of feed efficiency by the difference between actual and expected feed intake. The relative abundance and activity of rumen microorganisms determine the feed efficiency of ruminants. In this study, rumen microflora of Tan sheep with high and low residual feed intake was analyzed. After the experiment, rumen fluid was collected from 7 male and female Tan sheep with extremely low RFI and 8 male and female Tan sheep with extremely high RFI. The amplicon of bacterial 16S rRNA gene in the rumen fluid samples of Tan sheep was sequenced by sequencing technology. The results showed that rumen microbial diversity and richness had no significant changes in male and female sheep (P > 0.05), and principal coordinate analysis (PCoA) showed no significant separation of rumen microbial community. However, in the extremely high group, the abundance of Bacteroidetes in male sheep was significantly higher than that in female sheep, the abundance of actinomycetes in female sheep was significantly higher than that in male sheep, and the abundance of proteobacteria in male sheep was significantly higher than that in female sheep (P < 0.05). In the extremely high group, the abundance of Olsenella was significantly higher in female sheep than in male sheep, the abundance of Prevotella was significantly higher in male sheep than in female sheep, and the abundance of Erysipelotrichaceae_UCG-002 was significantly higher in male sheep than in female sheep (P < 0.05). Selenomonas bacteria was significantly higher in male sheep than in female sheep in the extremely low group (P < 0.05). Among the different RFI phenotypes of RAMS, Methanobrevibacter in euryarchaea in low RFI group was significantly higher than that in high RFI group, and Proteobacteria in low RFI group was significantly lower than that in high RFI group (P < 0.05). In conclusion, gender is an important factor affecting rumen microbial differences, and Methanobrevibacter flora in rumen is associated with low RFI tan sheep.