Comparison of energy metabolism and meat quality among three pig breeds.

The objective of this study was to evaluate the effects of muscle-fibre types and hormones on glycolytic potential and meat quality traits and their association with glycolytic-related gene expression in three different altitude pig breeds. The pig breeds studied were the Tibetan pig (TP, high altitude), the Liang-Shan pig (LSP, middle altitude) and the Duroc×(Landrace×Yorkshire) cross (DLY, flatland). The results indicated that TP and LSP had better meat quality than DLY (P<0.01). The glycolytic potential (GP) increased in the order of TP<LSP<DLY and decreased with time post mortem. DLY had higher glucagon and epinephrine contents than LSP and TP (P<0.01). The proportions of myosin heavy chain muscle fibers type I in the Longissimus dorsi increased in the order of DLY<TP<LSP, whereas the proportion of type IIb increased in the order of TP<LSP<DLY. The expression of gene PKM2 played an important role in the glycolysis rate of the different genotypes. Compared with the other two pig breeds, the high-altitude breeds had better meat quality attributes, which may be due to the slow rate of glycolysis metabolism.