| After long-term natural selection and artificial breeding, Ujumqin sheep have been formed an excellent variety on Ujumqin grassland. The changes of nutritional composition and intramuscular fat gene of Ujumqin sheep in the process of the natural grazing were studied in this study.1,3,6,9,12and18months aged Ujumqin sheep were explored and discussed the changes of the nutrients and intramuscular fat-related genes expression in three parts of skeletal muscles (M. biceps femoris, M. longissimus dorsi and M. triceps brachii) with the growth. The results shows that the content of moisture and ash are decreased significantly with the growth (P<0.05). The content of crude protein was lower at the3month aged than that of others, while no significant difference was observed in other aged of Ujumqin sheeps. The content of fat was higher at the aged of9and18months while lower at the aged of3and12months than that of others. The smaller changes of moisture, crude protein, ash were observed than that of fat in different parts of skeletal muscle with influenced by environment. The PPARy gene expression was higher at the aged of1and12months, as well as was lower expression at the9and18months aged than that of other months. The FAS gene expression was higher at3and12months aged, also lower expression was observed at9and18months aged Ujumqin sheeps than that of other months. The PPARy and FAS gene expression trends were similar to that the three parts of skeletal muscles. The expression of PPARy and FAS gene are negatively correlated with the content of intramuscular fat, which may be resulted from the different seasons and different herbage. The resolving the changes of nutritional composition and intramuscular fat gene expression of Ujumqin sheep with growth is particularly important to that the correlation between meat property (physical and chemical) and quality. Also it is important scientific meanings for that improvement of meat quality and meat production. |
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