运动对苏尼特羊肌纤维组织学特性和肉品质的影响及其调控机理

本试验以6月龄苏尼特羊为研究对象,采用肌球蛋白重链(MyHC)分子分型法、ATP酶染色法分析肌纤维组织学特性,并对肉品质指标、能量代谢相关基因mRNA相对表达量、代谢酶活性进行测定及分析,以探究运动对苏尼特羊肌纤维特性和肉品质的影响及其调控机理.选取体况良好、平均体重为(19.77±3.81)kg的3月龄苏尼特羊14只...

Effects of Exercise on Muscle Fiber Histological Characteristics and Meat Quality of Sunit Sheep and Its Regulatory Mechanism

The effects of exercise on muscle fiber histological characteristics,meat quality of Sunit sheep were investigated in this experiment using 6?month?old Sunit sheep as research object.The fiber histological charac?teristics were analyzed by myosin heavy chain(MyHC)molecular classification method and ATPase staining method,and the meat quality indexes,the mRNA relative expression levels of energy metabolism related genes and the activities of metabolic enzymes were also measured.Fourteen Sunit sheep with the average body weight of(19.77±3.81)kg were randomly divided into 2 groups:control group and exercise group,each group had 7 sheep.The sheep in the control group and exercise group were raised in a semi?open sheep shed,and the ex?ercise group carried out 6 km driving exercise every day under the same environment.The pre?test period lasted for 7 days and the test period lasted for 90 days.The results showed that the diameter and cross?sectional area of typeⅠmuscle fiber,the number proportion,diameter,cross?sectional area and area proportion of typeⅡa muscle fiber in the exercise group were significantly or extremely significantly higher than those in the control group(P<0.05 or P<0.01),while the density of muscle fiber,area proportion and number proportion of type IIb muscle fiber in the exercise group were significantly or extremely significantly lower than those in the con?trol group(P<0.05 or P<0.01).2)The activities of lactate dehydrogenase(LDH)and succinate dehydrogen?ase(SDH)and the mRNA relative expression levels of MyHCⅡa,MyHCⅡx,AMP?activated protein kinaseα1(AMPKα1),peroxisome proliferator?activated receptor gamma co?activator?1α(PGC?1α),cytochrome C oxidaseⅣ(COXⅣ)in muscle of sheep in the exercise group were significantly or extremely significantly higher than those in the control group(P<0.05 or P<0.01).3)The initial pH,the values of redness(a^?),yellowness(b^?),brightness(L^?),saturability of muscle in the exercise group were significantly or extreme?ly significantly lower than those in the control group(P<0.05 or P<0.01),and the shear force and pH_(24 h) were significantly or extremely significantly higher than those in the control group(P<0.05 or P<0.01).In summa?ry,exercise can enhance the muscle oxidative metabolism of Sunit sheep,promote the formation of oxidized muscle fiber,and effectively delay the pH decline after slaughter,but no improvement in muscle color and ten?derness.Chinese Journal of Animal Nutrition,2022,34(2):1140?1150]