Study On The Correlations Of Muscle Fiber Histochemical Characteristics, MyHC Gene And Meat Quality Of Bamei Sheep

The aim of this study was investigate the corellations of muscle fiber histochemical characteristics, MyHC gene and meat quality from three different slaughter weights in longissimus dorsi, biceps femoris, triceps brachii, supraspinatus and semitendinosus muscles of Bamei sheep by ATPase histochemical staining and real-time PCR techniques. The results showed as follows:The diameters and cross-sectional areas of three types’ muscle fiber from five anatomical locations were increased with slauter weight of Bamei sheep, and thirty-eight related datas were significantly increased with the slaughter weight (p<0.05). The proportions by number of type I and type IIA muscle fibers from 30-40kg sheep were higher than 50-60kg ones, while for proportions by number of type IIB, the opposite trend was observed, and there were six significantly related datas(p<0.05). The trends of diameters and cross-sectional areas of three types’ muscle fiber from five anatomical locations were type I< type IIA< type IIB. The trends of proportions by number and area of three types’ muscle fiber from supraspinatus muscle were type I< type IIA< type IIB, but for other anatomical locations, the trends were type IIA< type I< type IIB.Not only the relative expression of MyHCIIx gene from five anatomical locations but also the relative expressions of MyHCI gene and MyHCIIb gene from triceps brachii and supraspinatus muscles were decreased with slauter weight of Bamei sheep, and thirteen related datas were significantly decreased with the slaughter weight (p<0.05). The expressions of MyHCI, MyHCIIa and MyHCIIx from supraspinatus muscle were higher than other anatomical locations, while for MyHCIIB gene, the trend was opposite, and there were nineteen significantly related datas(p<0.05). The trend of expression among four types’ MyHC gene from longissimus dorsi muscle was MyHCIIa< MyHCI< MyHCIIx< MyHCIIb, but for other anatomical locations, the trend was MyHCIIa< MyHCIIb< MyHCIIx< MyHCI.Slaughter weight was correlated positively with the diameters and cross-sectional areas of three types’ muscle fiber from biceps femori and supraspinatus muscles of Bamei sheep, also positively with the proportions by number and area of type IIB muscle fiber, but negatively with the proportions by number and area of type I and type IIA muscle fibers, and four correlation coefficients were significant(p<0.05), twelve were highly significant(p<0.01). The Warner-Bratzler shear force had positive correlation with the proportions by number of type Ⅰ and type ⅡA muscle fiber, but negative correlation with the cross-sectional area of type ⅡA and ⅡB muscle fiber, and three correlation coefficients were significant(p<0.05), two were highly significant(p<0.01).The the relative expressions of four types’ MyHC gene from longissimus dorsi, triceps brachii, supraspinatus and semitendinosus muscles of Bamei sheep was negatively correlated with a* value, but positively correlated with Warner-Bratzler shear force, and there were ten significant correlation coefficients (p<0.05), thirteen highly significant correlation coefficients (p<0.01).