Abstract: The aim of this study was to investigate the effect of different feeding regimes (grazing and stall feeding) on slaughter performance, meat quality and lipid oxidation of Triceps brachii muscle in 12-month-old Sunit sheep. The fatty acid composition of muscles was determined by high performance liquid chromatography (HPLC) and gas chromatographymass spectrometry (GC-MS). The results showed that the live mass, carcass mass and net meat mass of stall-fed sheep were significantly higher than those of grazing sheep (P < 0.05). A significant increase in meat lightness (L*) and yellowness (b*) was observed comparing grazing and stall-fed sheep, whereas the opposite was found for shear force (P < 0.05). There were no differences in the contents of protein and cholesterol between the two groups (P > 0.05). The content of intramuscular fat in grazing sheep was significantly lower than that in stall-fed sheep (P < 0.05). The percentage of polyunsaturated fatty acids in grazing sheep was higher than that in stall-fed sheep (P < 0.05), especially conjugated linoleic acid, α-linolenic acid, eicosapntemacnioc acid and docosahexaenoic acid. After three months of storage, the thiobarbituric acid value in grazing sheep was lower than that in stall-fed sheep (P < 0.05), indicating that meat from grazing sheep has higher antioxidant capacity. Stall-fed sheep had better slaughter performance and were more suitable for processing, while the nutritional value of meat from grazing sheep was higher. In practice, different feeding regimes should be chosen according to the use of mutton.

Key words: feeding regime, slaughter performance, meat quality, fatty acid, lipid oxidation