Study On The Relationship Between The Muscle Fiber Types With Meat Quality Traits Of Bama Xiang Pig

In this article, the Bama Xiang pigs and Landraces were used as the experimental animals, and the different of their carcass and meat quality traits were studied. The gene expression laws of MyHC I, MyHC IIA、MyHC IIB, MyHC IIX, PGC-la, and AMPK in longissimus muscles of (1,30,6,90,180,300days) Bama Xiang pigs and (1,30,60,90,180days) Landraces were detected by QRT-PCR method. The activity and variation of Lactate dehydrogenase (LDH), Succinic dehydrogenase (SDH), Malate dehydrogenase (MDH) in longissimus muscles of two species pigs were analyzed. The relationship between the muscle fiber types with meat quality in two species pigs was determined.1. There were significantly differences of carcass traits between180day-old Bama Xiang pigs and Landraces. The backfat thickness of Bama Xiang pigs were significantly higher than that of Landraces, but the weight and the eye muscle area of Bama Xiang pigs significantly lower than that of Landraces. The weight and the eye muscle area of300day-old Bama Xiang pigs were also significantly lower than that of Landraces. The intramuscular fat content of Bama Xiang pigs were higher than that of Landraces, however the muscles conductivity values lower than that of Landraces. 2.The MyHC I gene expression in longissimus muscle of Bama Xiang pigs were significantly higher than that of Landraces in30,60day-old, and this gene expression in300d Bama Xiang pigs’longissimus muscle were significantly higher than that of180d Landraces. The MyHC IIA gene expression in longissimus muscle of Bama Xiang pigs were significantly higher than that of Landraces in60,180days-old, and this gene expression in300d Bama Xiang pigs’longissimus muscle were significantly higher than that of180d Landraces. The MyHC IIX gene expression in longissimus muscle of Bama Xiang pigs were significantly higher than that of Landraces in1,180day-old, and this gene expression in300d Bama Xiang pigs’longissimus muscle were significantly higher than that of180d Landraces, but its expression were significantly lower than that of Landraces in30day-old. The MyHC IIB gene expression in longissimus muscle of Bama Xiang pigs were significantly lower than that of Landraces in30,60,90day-old, and this gene expression in300d Bama Xiang pigs’longissimus muscle were also significantly lower than that of180d Landraces, but its expression were significantly higher than that of Landraces at1day-old. We analyzed the correlation between these genes expression with carcass traits showed that there were a significantly positive correlation between the expression of MyHC I gene with backfat thickness and intramuscular fat content; had significantly positive correlation between the MyHC IIB gene expression with dressing percentage, but it was significantly negative correlation with intramuscular fat content. These results indicated that good meat quality of Bama Xiang pigs, especially high intramuscular fat content, was possibly associated with more oxidized muscle fiber content in longissimus muscle. 3.The activity of LDH which it wathe key enzyme of glycolytic pathway in Bama Xiang pigs’ longissimus muscle was significantly higher than that of Landraces in30and90day-old, but the muscle LDH activity of Bama Xiang pigs was significantly lower than that of Landraces in180day-old. The activity of SDH which it was the key enzyme of aerobic metabolism in30d Bama Xang pigs’ longissimus muscle was significantly higher than that of same age Landraces, its activity in300d Bama Xang pigs was also significantly higher than that of180d Landraces. There was no significantly different between Bama Xiang pigs and Landraces about the activity of MDH, however, mostly the MDH activity in Bama Xiang pigs was high. The shear-force of muscle of pigs had positive correlation with LDH activity.4. The expressions of PGC-la gene in Bama Xang pigs’ longissimus muscle was significantly higher than that of Landraces in1,60,180days-old, and PGC-1α gene expression of300d Bama Xang pigs muscle was also significantly higher than that of180d Landraces. The expressions of AMPK gene in180d and300d Bama Xang pigs’ longissimus muscle were significantly higher than that of180d Landraces.There was a significantly positive correlation between the genes expression of PGC-la and AMPK with oxidized muscle fiber Ⅰ and ⅡA in pigs.