Comparison Of The Muscle Fiber Traits And Expression Level Of Myh6 Gene Of Two Rabbit Breeds

With a growing demand for meat diversity, rabbit meat is more and more popular. We should pay attention to improve the quality and yields of rabbit meat. Muscle fiber traits directly affect the quality of meat. The eating characteristics (tenderness, flavor and juiciness) are closely related to the number, size, density, and types of muscle fiber. In this study, the experiments were carried out with Fujian yellow rabbits and New Zealand white rabbits, then we did the correlation analysis between the expression level of Myh6 in different weeks and muscle fiber traits of back and leg muscles to provide the theoretical basis for some improvement in rabbit meat.In this study, muscle fiber traits of two rabbit breeds in different weeks were analyzed by frozen section technique and quantitative PCR analysis of Myh6. The main results are as follows:1. The density, area, long and short diameters of three different types of Fujian yellow rabbits’ and New Zealand white rabbits’muscle fiber were analyzed with the frozen section technique. In Fujian yellow rabbits’and New Zealand white rabbits, the diameter of white muscle fibers was 8-10μm at 2 week and 17-24μm at 12 week, short diameter was 5μm at 2 week and 10-16μm at 12 week. The diameter of intermediate muscle fibers was 6-10μm at 2 week and 17-22μm at 12 week, short diameter was 4-5μm at 2 week and 11-15μm at 12 week. The diameter of red muscle fibers was 6-9μm at 2 week and 16-21μm at 12 week, short diameter was 3-5μm at 2 week and 10-13μm at 12 week. The area of white muscle fibers was 22-32μm2 at 2 week and 117-191μm2 at 12 week, the area of intermediate muscle fibers was 13-27μm2 at 2 week and 85-183μm2 at 12 week, the area of red muscle fibers was 10-21μm2 at 2 week and 95-130μm2 at 12 week. The density of white muscle fibers was 3300-5400/mm2 at 2 week and 530-840/mm2 at 12 week, the density of intermediate muscle fibers was 1900-3400/mm2 at 2 week and 340-470/mm2 at 12 week, the density of red muscle fibers was 1600-3200/mm2 at 2 week and 300-400/mm2 at 12 week. The results showed that the density of white muscle fibers was significantly greater than the red muscle fibers and intermediate muscle fibers, but there was no significant difference between the red muscle fibers and intermediate muscle fiber density; the area of white muscle fibers was larger than intermediate muscle fibers, and the area of intermediate muscle fiber was larger than red muscle fiber area, but both no significant differences (P>0.05). The area of white muscle fiber was significantly higher than red muscle fibers (P<0.05). The diameter and short diameter of white muscle fiber was slightly larger than the intermediate muscle fibers, diameter and short diameter of intermediate muscle fiber was slightly larger than red muscle fibers, but the difference was not significant. Muscle fiber density, area, long and short diameters between gender, varieties, back and legs were not significantly different. The density was smaller with increases of the number of weeks, but area, long and short diameters were gradually larger.2. We analyzed the expression level of the Myh6 gene in each week by quantitative PCR. The results showed that the expression level of Myh6 gene increased first, then decreased, and to stable trend. The expression level of Myh6 gene in male rabbits was greater than females. The expression level of Myh6 gene in New Zealand White rabbits was greater than Fujian yellow rabbit. These results were consistent with the results of muscle fiber area, long and short diameters. It suggests that Myh6 gene may contribute to the development of muscle fibers.