日粮不同蛋白质水平对猪骨骼肌钙蛋白酶抑制蛋白和钙蛋白酶基因表达及嫩度的影响

Effects of Different Protein Levels on Calpastatin and μ-calpain mRNA Relative Expression in Skeletal Muscle and Muscle Tenderness in Pigs

为研究饲料不同蛋白质含量对calpastatin和μ-calpain mRNA在骨骼肌中的表达量,选用54头约50kgLY(长×大)二元杂交去势公猪,随机分为3个处理,每个处理3个重复,每个重复3头猪,分别饲喂蛋白质水平为10%、18%和26%的日粮,各日粮能量及氨基酸模式保持一致,饲养76d后屠宰取样,用荧光相对定量PCR测定猪背最长肌中calpastatin和μ-calpain mRNA在骨骼肌中的表达量,及其对剪切力的影响。结果表明,日粮不同蛋白质水平对calpastatin和μ-calpain mRNA在骨骼肌中的表达量有显著影响(P<0.01)。calpastatin mRNA在骨骼肌中的表达量随日粮蛋白质水平的升高而升高。μ-calpain mRNA在骨骼肌中的表达量随日粮蛋白质水平的升高而下降。骨骼肌剪切力与calpastatin表达量显著正相关,骨骼肌中calpastatin mRNA的表达量越高,骨骼肌剪切力值越高(P<0.01),相关系数为0.859。骨骼肌剪切力与μ-calpain显著负相关,骨骼肌中μ-calpain mRNA的表达量越高,骨骼肌剪切力值越低(P<0.05),相关系数为-0.748。骨骼肌中calpastatin mRNA的表达量与μ-calpain mRNA的表达量显著负相关,calpastatin mRNA表达量越高,μ-calpain mRNA的表达量越低(P<0.01),相关系数为-0.875。即日粮不同蛋白质水平对calpastatin和μ-calpain mRNA在骨骼肌中的表达量有显著影响。

To investigate the effects of different dietary protein levels on the relative expression of calpastatin and μ-calpain mRNA in skeletal muscle and their relationships with muscle tenderness. Fifty-four dual hybrid castrated boars about 50 kg LY （Landrace x Yorkshire） were randomly allocated into three treatments with three replicates for each and three pigs per replicate, and fed with diets of three protein levels （10%, 18% and 26%）respectively. The energy level and amino acid pattern in the three diets were kept the same. The whole feeding trial lasted for 76 days, then fluorescent relative quantitative PCR was used to determine the relative expression of calpastatin and μ-calpain mRNA in skeletal muscle and their effects on the shear force. The results showed that 1） different levels of dietary protein had significant effects on the relative expression of calpastatin and μ-calpain mRNA in skeletal muscle （P〈0.01）. With the increase of protein content, the relative expression of calpastain increased, while that of μ-calpain decreased; 2） the shear force of skeletal muscle was significantly positively correlated with calpastatin mRNA expression, with Pearson Correlation= 0. 859 （P〈0.01）, but a negative correlation existed between the shear force and μ-calpain mRNA expression, with Pearson Correlation = -0. 748 （P〈0.05）; 3） the calpastatin mRNA expression was negatively correlated with the μ-calpain mRNA expression, with Pearson Correlation = - 0. 875 （P〈0.01）. In conclusion, different dietary protein levels had significant effects on the relative expression of calpastatin and μ-calpain in skeletal muscle .