摘要
为考察不同部位牛肉肌纤维类型的差异、比较两种肌纤维分型方法、研究肌纤维类型对宰后成熟过程中组织蛋白酶活性的影响,选取新疆褐牛冈下肌、菱形肌、背最长肌、背阔肌、腰大肌、股二头肌、半腱肌、腓肠肌共8个部位的牛肉,分别用ATPase染色法和RT-PCR法检测肌纤维类型组成和MyHC基因相对表达量,用Image-Pro Plus 6.0软件分析ATPase染色图像,计算各类型肌纤维的面积和直径,并检测各部位牛肉宰后成熟0、3、7、9、11、14 d时组织蛋白酶B、L、H活性。结果表明:新疆褐牛不同部位肉的肌纤维类型组成不同,两种肌纤维类型的分型方法在确定Ⅰ型肌纤维数量时呈极显著相关,在8个部位牛肉中,均没有发现MyHCⅡb型基因的表达,ATPase染色法确定的ⅡB型肌纤维数量百分比与RT-PCR法确定的MyHCⅡx型基因表达百分比呈显著正相关,与MyHCⅡa型基因表达百分比呈极显著负相关。两种确定肌纤维类型的方法存在一定的相关性,ATPase染色法确定的ⅡB型肌纤维可能与RT-PCR法确定的MyHCⅡx基因相对应。在宰后成熟过程中,各部位牛肉组织蛋白酶活性基本表现为先升高、后降低的趋势,不同部位的牛肉达到活性最大值的时间不同;组织蛋白酶H活性非常低,相比于组织蛋白酶B和L,其在宰后成熟中的作用可以忽略不计,组织蛋白酶L活性是B活性的2.5~4倍,在宰后成熟中起更重要的作用。Ⅰ型肌纤维数量与宰后9、11 d组织蛋白酶B和L活性呈显著甚至极显著正相关关系,在新疆褐牛各部位肉中含有的Ⅰ型肌纤维越多,组织蛋白酶活性越高,越有利于牛肉宰后成熟嫩化。
Lysosomal cathepsins are enclosed in the lysosomes,which could be released into the cytosol as a consequence of lysosomal disruption occurring after cell death.It was approved that cathepsins played an important role in the degradation of myofibrillar protein in beef during postmortem aging.Despite its significance,there was little information about the correlation between cathepsins and muscle fiber types in beef during postmortem aging.The objectives were to compare the results of ATPase staining and RT-PCR in typing muscle fibers,find out the relationship between muscle fiber type and the activity of cathepsins,and reveal the possibility that muscle fiber types affect meat quality through cathepsin activity.Eight different parts of the muscles(Semitendinosus,Latissimus dorsi,Longissimus thoracis,Infraspinatus,Biceps femoris,Gastrocnemius,Rhomboideu and Psoas major)in Xinjiang brown cattle were removed from the left side of each carcass.The muscle fiber type composition,fiber diameter and fiber cross-sectional area were detected by ATPase staining,and MyHC gene expression of each muscle was determined by RT-PCR.The changes of cathepsin B,L,H activity were investigated at 0 d,3 d,7 d,9 d,11 d and 14 d during postmortem aging,respectively.The results showed that the composition of muscle fiber types in different parts of Xinjiang brown cattle was quite different.There was a significant correlation(p<0.01)between the two methods when they were used to quantify the muscle fiber typeⅠand MyHCⅠgene expression.However,muscle fiber typeⅡand the expression of MyHCⅡgene could not match very well.The proportion of muscle fiberⅡB was negatively correlated(p<0.05)with the expression of MyHCⅡa and positively correlated(p<0.05)with the expression of MyHCⅡx.MyHCⅡb was not found in eight muscles of Xinjiang brown cattle.It could be inferred that there was a correlation between the expression pattern of MyHC gene and the location of muscle.The activity of cathepsin was increased gradually during senescence after
作者
丰永红
李海鹏
张松山
谢鹏
徐晨晨
孙宝忠
FENG Yonghong;LI Haipeng;ZHANG Songshan;XIE Peng;XU Chenchen;SUN Baozhong(Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2020年第7期355-364,共10页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(31571910)
中央级公益性科研院所基本科研业务费专项资金项目(2016ywf-yb-13)
国家肉牛牦牛产业技术体系项目(CARS-37)
河北省现代农业产业技术体系肉牛产业创新团队建设项目(HBCT2018130204)。
