苏尼特羊的肌纤维特性分析

Analyzing the muscle fiber characteristics of Sunit sheep

取5、6、8三个月龄的苏尼特羊背最长肌(M.Longissimus dorsi,LD)、股二头肌(M.Biceps femoris,BF)和臂三头肌(M.Triceps brachii,TB)为实验材料,采用ATP酶组织化学染色法染色分型。分析不同部位、不同月龄对苏尼特羊肉肌纤维特性的影响,为通过调控肌纤维类型转化从而改善肉质建立一定的理论基础。结果显示,三个部位均以糖酵解型肌纤维(ⅡB型)为主。苏尼特羊Ⅰ型肌纤维的数量比例为臂三头肌和股二头肌显著大于背最长肌(p<0.05),而Ⅰ型肌纤维的面积比例、ⅡA型肌纤维的数量比例和面积比例、ⅡA型和ⅡB型肌纤维的直径和横截面积均为臂三头肌显著大于股二头肌(p<0.05),而股二头肌又显著大于背最长肌(p<0.05);苏尼特羊背最长肌中Ⅰ型肌纤维的数量比例5月龄显著高于6、8月龄(p<0.05),ⅡA型肌纤维的数量比例8月龄显著高于5、6月龄(p<0.05)。Ⅰ型肌纤维直径,ⅡA型的面积比例、ⅡA型肌纤维直径和横截面积均为5月龄显著小于6、8月龄(p<0.05)。

This study was to investigate the difference in muscle fiber characteristics of Longissimus dorsi（LD）, Biceps femoris（BF） and Triceps brachfi（TB） muscles obtained from Sunit sheep at 5,6 and 8 months of age, respectively. The aim of study was to obtain theoretical knowledge through regulating the muscle fiber type transformation so as to improve the meat quality. The variety muscle fiber types were classified by histochemical analysis of the myosin ATPase method with an acid preincubation solution（pH4.6）. The results showed that fiber number percentage of type II B was most common in three anatomical locations. Fiber number percentage of type I in TB and BF were significantly higher than that in LD（p〈0.05）. The area percentage of type I , fiber number and area percentages of type II A,the diameter and cross-sectional area of type II A and II B in TB were significantly higher than that in BF（p〈0.05）,that in BF were significantly higher than in LD（p〈0.05）. Fiber number percentage of type I in LD of 5 months of age was significantly higher than that of 6 and 8 months of age（p〈0.05）,however,fiber number percentage of type II A in LD of 8 months of age was significantly higher than that of 5 and 6 months of age（p〈0.05）. The diameter of type I ,fiber area percentage and diameter and cross-sectional of type II A of 5 months of age were significantly lower than that of 6 and 8 months of age（p〈0.05）.