Abstract:

The objective of this study was to characterize the profile of muscle fibres from the same muscle (biceps femoris,BF) among different breeds (Sunit sheep, Bamei sheep and Small Tail Han sheep) by histochemical analysis. Six Sunitsheep, ten Bamei sheep and ten Small Tail Han sheep were slaughtered at 6 months of age. Ovine skeletal muscle fibreswere classified using the myosin ATPase staining technique with an acid preincubation solution (pH 4.6), into three types(Ⅰ, ⅡA and IIB). The fiber number, area percentage, diameter and cross-sectional area of each fiber type were studied.The relationship between fiber types and meat quality of Sunit sheep traits was also examined. The results showed that fibernumber percentage of type IIB was the most common in BF muscle of three breeds. The fiber number, area percentages anddiameter of type Ⅰ in Sunit sheep were significantly lower than those in Bamei sheep (P ＜ 0.05). The cross-sectional area oftype Ⅰ and the fiber area percentage of type ⅡA and were significantly lower than those in Bamei sheep and Small Tail Hansheep (P ＜ 0.05). The cross-sectional area of type ⅡB was significantly lower than that in Small Tail Han sheep (P ＜ 0.05).For Sunit sheep, fiber density in BF muscle had a positive correlation with fat content (P ＜ 0.05) and a negative correlationwith WBSF. Fiber number percentage of type ⅡB had a negative correlation with ultimate pH (P ＜ 0.05).

Key words: Sunit sheep, muscle fiber characteristics, mutton quality