Effects of Cold-Season Supplementary Feeding on the Rumen Microbiota and Metabolite Profiles of Tibetan Sheep

This study aimed to investigate the effects of cold-season supplementary feeding on rumen microbiota and metabolite composition in Tibetan sheep. Thirty healthy 1.5-year-old Tibetan ewes with similar body condition were selected and randomly assigned to two groups: a grazing group (n = 15) and a supplementary feeding group (n = 15). The experimental period lasted for two months. At the end of the trial, rumen fluid samples were collected for metagenomic and metabolomic analyses. The results showed that the relative abundances of Pseudomonadota, Treponema, Clostridium, and Butyrivibrio were significantly increased in the supplementary feeding group, while the abundance of Euryarchaeota was significantly decreased. KEGG pathway analysis indicated that arachidonic acid metabolism and phenylalanine metabolism were significantly downregulated in the supplementary feeding group. CAZy analysis revealed that the gene abundances of glycoside hydrolase families GH24 and GH130 were significantly upregulated. Metabolomic analysis identified a total of 603 differentially abundant metabolites between the two groups, among which 193 metabolites, including L-lysine, L-arginine, glycine, hydroxyproline, 5-aminovaleric acid, creatine, and creatinine, were significantly upregulated, whereas 410 metabolites, such as prostaglandin F2alpha and leukotriene B4, were significantly downregulated. Correlation analysis showed that Treponema and Butyrivibrio were significantly positively correlated with the levels of glycine, hydroxyproline, 5-aminovaleric acid, creatine, and creatinine. In conclusion, cold-season supplementary feeding improves energy utilization efficiency, enhances amino acid metabolism, and alleviates inflammatory responses in Tibetan sheep by regulating the rumen microbial community structure and its metabolic functions, thereby improving their adaptability to cold environments.