Exploring the Role of Rumen Microbiota and <i>KLF15</i> Gene in the Performance of Growing Hu Sheep

Exon mutations and the rumen microbiome play crucial roles in influencing growth performance in meat animals, making them key factors for enhancing meat production efficiency. This study aimed to further investigate the effects of host genetics (KLF15 c.6256511 A>G) and rumen microorganisms on the growth performance of Hu sheep. This study selected 50 growing Hu sheep with extreme body weight and uniformly fed them a diet with a concentrateto-roughage ratio of approximately 1.5:1. Rumen content samples were collected for 16S rDNA sequencing. Growth traits and feed efficiency were measured at 80, 100, 120, 140, 160, and 180 days of age. The high body weight (H-BW) group exhibited better production performance, with significant differences found in growth traits, slaughter traits, and fat deposition traits between the H-BW and low weight (L-BW) group (P < 0.05). Among the 23 different bacterial genera identified, Rikenellaceae_RC9_gut_group was significantly correlated with 180-day body weight and muscle fat content of Hu sheep. The relative abundance of Rikenellaceae_RC9_gut_group was lowest in Hu sheep with the AA genotype (P < 0.05). No significant difference in rumen microbial diversity was observed between the H-BW and L-BW groups. Rikenellaceae_RC9_gut_group may activate the mTOR signaling pathway through the metabolic pathway of valeric acid, promote the growth of muscle cells, and thus regulate the body weight of Hu sheep. Utilizing the KLF15 c.6256511 A>G mutation site and the Rikenellaceae_RC9_gut_group provides a valuable approach to enhance the growth traits and overall production performance of Hu sheep.