Effects of feeding patterns on production performance, lipo-nutritional quality and gut microbiota of Sunit sheep

This study aimed to investigate the impact of feeding patterns on the production performance, lipo-nutritional quality, and gut microbiota of Sunit sheep. A total of 24 sheep were assigned to two groups: confinement feeding (CF) and pasture feeding (PF) groups. After 90 days, the CF group exhibited significantly increased average daily gain, carcass weight, backfat thickness, and intramuscular fat content of the sheep, whereas the PF group showed significantly increased pH_24h and decreased L^∗ value and cooking loss of the longissimus lumborum (LL) muscle (P < 0.05). In the PF group, the contents of linoleic, α-linolenic, and docosahexaenoic acids were considerably higher and the n-6/n-3 polyunsaturated fatty acid ratio was significantly lower (P < 0.05). Furthermore, the triglyceride, cholesterol, and nonesterified fatty acid levels in the serum of the CF group significantly increased, whereas the enzyme contents of fatty acid synthase (FASN) and hormone-sensitive lipase (HSL) in the LL muscle of the PF group were markedly elevated (P < 0.05). The PF group also showed altered expression of lipid metabolism-related genes, including upregulated FASN, HSL, fatty acid binding protein 4 (FABP4), and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) (P < 0.05). Meanwhile, differences were observed in the abundance of key bacteria and microbiota functions between the groups. Correlation analysis revealed that production performance and lipid metabolism may be related to the differential effects of bacteria. In conclusion, the transition in the feeding patterns of Sunit sheep caused changes in the gut microbial community and lipid metabolism level in the muscle as well as differences in fat deposition and meat quality.