Abstract: The aim of this study was to investigate the effects of different feeding patterns (grazing alone and combined with barn feeding) on the fatty acid composition of longissimus dorsi, the abundance of intestinal flora, facel short chain fatty acid and plasma lipid parameters in Sunit sheep aged 12 months by high throughput sequencing and gas chromatography-mass spectrometry (GC-MS). The results showed that at the genus level, the abundance of Bacteroides, Alistipes, and Phocaeicola in the grazing plus bran feeding group was significantly higher, while the abundance of Fibrobacter and Ruminococcus was significantly lower than in the grazing group (P < 0.05). The contents of fecal acetate and butyrate in the grazing group were significantly lower (P < 0.05), whereas the content of fecal propionate was significantly higher than in the grazing plus barn feeding group (P < 0.05). The plasma concentrations of triglyceride and high density lipoprotein cholesterol in the two groups were significantly different (P < 0.05). The contents of α-linolenic acid, eicosapntemacnioc acid (EPA), docosahexaenoic acid (DHA) and conjugated linoleic acid (CLA) in muscle from the grazing group were significantly higher than those in the grazing plus bran feeding group (P < 0.05). Correlation analysis showed that α-linolenic acid and CLA of longissimus dorsi muscle were positively correlated with the abundance of Fibrobacter, Ruminococcus and Alistipes (P < 0.05) but negatively correlated with Bacteroides (P < 0.05). Fecal acetic acid was negatively correlated with α-linolenic (P < 0.05) while fecal propanoic acid content was positively correlated with EPA and DHA (P < 0.05). This study concluded that meat from grazing sheep has better nutritional value and that the combination of grazing with barn feeding can change the intestinal flora of sheep to improve meat quality.

Key words: intestinal flora, fatty acid, plasma lipid parameters, Sunit sheep