Abstract: In order to explore the effect of exercise on the lipid metabolism and meat quality of Sunit sheep, a total of 12 (3-month-old) Sunit sheep with good body condition and body mass of (20.22 ± 0.68) kg were selected and randomly divided into a control group and an exercise group. The animals in the control group were housed in semi-open pens, while those in the exercise group were subjected to exercise by driving about 6 kilometers every day under the same housing environment. The pre-experiment lasted for 7 days and the formal experiment lasted for 90 days. The body mass was measured before slaughter, and Longissimus dorsi muscle was harvested after slaughter for determining meat quality attributes, fatty acid composition and the expression of genes associated with lipid metabolism by gas chromatography-mass spectrometry (GC-MS), and real-time fluorescent quantitative polymerase chain reaction (PCR). The results showed that the slaughter performance (live body mass and back fat thickness) and meat quality (intramuscular fat content, pH, and the color parameters L*, a* and b* values) of the exercise group were significantly lower than those of the control group (P < 0.05) and the meat tenderness was worse than that of the control group. The relative content of saturated fatty acids in lamb meat from the exercise group was slightly lower than that in the control group, while the relative content of n-3 unsaturated fatty acids was significantly lower than that in the control group (P < 0.05). Compared with the control group, the relative expression levels of the hormone-sensitive triglyceride lipase (HSL), fatty acid synthetase (FASN), zinc finger protein PRDM16 (positive regulatory domain containing 16, PRDM16), and uncoupling protein1 (UCP-1) genes in the exercise group were significantly up-regulated (P < 0.05). In general, exercise for 90 days can improve the lipid metabolism of Sunit sheep, but decrease the meat quality.

Key words: Sunit sheep; meat quality; fatty acid composition; lipid metabolism-related genes