PRKAG3基因在不同品种猪不同生长阶段骨骼肌中的表达差异及其表达量与肉质的关系

摘要

本试验中旨在比较PRKAG3基因在不同品种猪不同生长阶段骨骼肌中的表达差异,并探讨PRKAG3基因与肉质的关系.挑选15 kg左右的汉普夏阉公猪17头和长撒阉公猪16头,饲喂相同饲粮,当体重分别达到20和50 kg时,2个品种的猪分别屠宰5头,体重达到100 kg时分别屠宰7和6头.各生长阶段屠宰后均测定骨骼肌pH、肌糖原含量以及PRKAG3基因表达量,且在100 kg阶段屠宰后同时测定肉质性状.结果表明:1)在不同生长阶段长撒猪骨骼肌中PRKAG3基因的表达量均高于汉普夏猪,特别是在100 kg阶段,长撒猪骨骼肌中PRKAG3基因的表达量是汉普夏猪的6.81倍(P<0.05).长撒猪与汉普夏猪骨骼肌中PRKAG3基因的表达量均随体重的增加而增加,但汉普夏猪不同生长阶段PRKAG3基因的表达量差异不显著(P>0.05),而长撒猪PRKAG3基因的表达量在100 kg阶段时显著高于20和50 kg阶段时(P<0.05).2)汉普夏猪和长撒猪的肉质存在差异.汉普夏猪的滴水损失和失水率显著高于长撒猪(P<0.05),而熟肉率、黄度(b)值极显著低于长撒猪(P<0.01),剪切力和pH2(屠宰后24 h的pH)显著低于长撒猪(P<0.05).与长撒猪相比,汉普夏猪具有较高的肌糖原含量(P>0.05).3)猪骨骼肌中PRKAG3基因的表达量与肉质的相关性存在品种效应.汉普夏猪骨骼肌中PRKAG3基因表达量与滴水损失呈正相关,与熟肉率呈负相关,与pH2呈显著负相关(P<0.05).长撒猪骨骼肌中PRKAG3基因表达量与滴水损失和失水率呈正相关,与pH2呈负相关.上述结果表明,猪骨骼肌中PRKAG3基因具有品种和生长阶段表达差异;猪骨骼肌中PRKAG3基因的表达量与肉质性状相关,特别是与pH2,二者呈显著负相关.%This study was conducted to compare the expression difference of PRKAG3 gene in skeletal muscle at different growth stages for different breeds of pigs, and to investigate the relationship between PRKAG3 gene expression level and meat quality. Seventeen Hampshire?sired barrows ( Hampshire pigs) and sixteen Land?rance?Saba barrows ( LS pigs) with about 15 kg weight body were fed with the same diet in individual pens. Five pigs of each breed of pigs were slaughtered at 20 and 50 kg, and 7 Hampshire pigs and 6 LS pigs were slaughtered at 100 kg, respectively, determining pH, muscle glycogen content, and PRKAG3 gene expres?sion, and additional determining meat quality traits at 100 kg. The results showed as follows:1) the expression level of PGKAG3 gene of LS pigs was higher than that of Hampshire pigs at different growth stages, and was 6.81 folds at 100 kg stage ( P<0.05) . PGKAG3 gene expression level was increased with the body weight in?creasing for the two breeds of pigs, and its expression level at 100 kg stage was significantly higher than that at 20 and 50 kg stages for LS pigs ( P<0.05) , but there were no significant differences at different growth stages for Hampshire pigs ( P>0.05) . 2) There was difference in meat quality between Hampshire pigs and LS pigs. Compared with LS pigs, Hampshire pigs had significantly lower pH2 ( pH at 24 h after slaughter) ( P<0.05) , shear force ( P<0.05) and yellowness ( b) value ( P<0.01) , significantly higher drip loss ( P<0.05) and wa?ter loss rate ( P<0.05) , and higher muscle glycogen content ( P>0.05) . 3) The correlation of PRGAKG3 gene expression level in skeletal muscle with meat quality was different between the two breeds of pigs. For Hampshire pigs, PRKAG3 gene expression level in skeletal muscle had a positive correlation with drip loss, but had a negative correlation with cooked meat percentage, and had a significant negative correlation with pH2 (P<0.05). For LS pigs, PRAKAG3 gene expression level in skeletal muscle had a positive correlation with drip loss or water loss rate, but had a negative correlation with pH2. These results suggest that PRKAG3 gene expression in skeletal muscle is changed with different growth stages and different breeds of pigs. PRKAG3 gene expression level is correlated with meat quality traits, especially with pH2, and there is a significant nega?tive correlation between them.