| This experiment uses 6,9,12,18 months Wuzhumuqin sheep as the research object,take the semitendinosus,longissimus dorsi,triceps brachii,biceps femoris after slaughter.First,using ATPase histochemistry staining method for muscle fiber dyeing,to find different months between different parts of the muscle fiber density,the percentage of the type,area ratio and diameter of the tendency of the histological features;Second,determination of different months Wuzhumuqin sheep skeletal muscle myosin heavy chain gene expression;Then,testing the sample quality indexes such as Hardness,Chewiness and Resilience.The result showed as followed:With increase of months the muscle fiber diameter is increased.the muscle fibers density decreased oppositely.We can know from the experiment that the percentage of type Ⅰ muscle fibers is less than type Ⅱ b muscle fibers in the muscle tissue,type Ⅱ a muscle fiber in between of the two above.In the whole,the increase of months type Ⅱ b muscle fiber content increased,especially type Ⅱ b in the longissimus dorsi have increased significantly.The result of myosin heavy chain gene expression,MyHC Ⅰ expression are slight increasing trend in 6 months to 9 months,The express are decreased in 12 months and 18months.MyHC Ⅱ a expression did not differ significantly between 6 months and 9 months,12 months begins to shrink,achieve the lowest point when 18 months.MyHC Ⅱ b and MyHC Ⅱ x expression changing is similar,with the increase of months increased significantly.With four parts of the same month MyHC Ⅱ b expression is significantly higher than in other areas in longissimus dorsi.From the data of Texture Analyzer;we can see with the increase of months skeletal muscle are becoming harder and the chewiness increased.The less months,the better meat tenderness.Longissimus dorsi changes the most obvious between four skeletal muscle.According to the data of correlation,the hardness and the chewiness negatively correlated with MyHC Ⅰ and MyHC Ⅱ a gene;positively correlated with MyHC Ⅱ x and MyHC Ⅱ b gene.Also the hardness and the chewiness negatively correlated with The density of muscle fiber;positively correlated with The muscle fiber diameter. |
