Composition of Myosin Heavy Chain Isoforms in Relation to Meat Texture in Duroc, Landrace and Meishan Pigs

抄録

Composition of myosin heavy chain (MyHC) isoforms in pig muscle was determined to study its effects on meat quality traits. Longissimus muscles of Duroc, Landrace and Meishan pigs were taken after slaughter from both sides of each animal. The muscle of one side was held at 40°C for 3h, followed by a storage at 4°C for 17h (40°C treatment), and one from the other side of the same animal was immediately held at 4°C for 20h (4°C treatment). Small pieces of the muscle were frozen after slaughter for the analysis of MyHC isoform composition by RT-PCR. Composition of the isoforms differed significantly in MyHC-2a, -2x, and-2b, and not in-slow among three breeds. The total percentage of MyHC-2x and -2b was more than 90% in each of three breeds, and the ratio of isoforms 2b/2x increased significantly in the order of Duroc⟩Landrace⟩Meishan. Meat quality analyses showed a higher cooking loss and poorer texture traits in Duroc than that in Landrace and Meishan at the 40°C treatment. On the other hand, no difference was found in quality traits at the 4°C treatment. These results suggested the effects of MyHC composition on the variation of meat texture traits.