Study On Muscle Fibre Growth And Development In Broiler And Genetic Effects Of Pax Gene

The growth and development of muscle fibre has definitely pertinence with the meat quality,especially diameter of muscle fibre and density of muscle fibre.The number of fibres has confirmed in chicken embryos and in the growth process of muscle fibre。The family of Pax play a critical role in cell proliferation and differentiation,which is considered to be the candidate genes of influencing the muscle characteristics.In this study, histology characteristics of muscle and development pattern of muscle fibre were studied in the random samples from Wenchang chicken,Rugao chicken and Anka chicken. The polymorphism of Pax-3,Pax-7 gene was investigated in thre chicken breeds. Analysis the expression of Pax-3 and Pax-7 genes in chest muscle and leg muscle of Rugao chicken by RQ-PCR. The main result were as follows:1. Analysis on phenotypic value of characteristics of chest muscle and leg muscle fibre of Rugao chicken showed that, chest muscle fibres diameter increased significantly from birth to 2 weeks old.The growth rate slowed down after 10weeks old.However, the density of the chest muscle fibre decreased with ages, and has been negatively correlation with the diameter.The diameter of leg mucle increased significantly in 2 weeks old and 8 weeks old,while the density decreased significantly in 2 weeks old,then decreased gradually.2. By using PCR-SSCP method to detect mutation of partial coding region of Pax-3 and Pax-7, there were totally three SNP locus detected in exon 6 of Pax-3 gene,which were: A/C at 62840 ,T/C at 62849 and T/G at 62932 mutated. There was one SNP locus detected in exon 6 of Pax-7 gene: T/C at 58300 mutated.3. Determination on expression of early growth trait of Pax-3 and Pax-7 gene by using RQ-PCR technology showed that, in chest muscle, expression peak of Pax-3 genes appeared about 8-20 days of embryo stage, then decreased rapidly and kept stable; in leg muscles Pax-3 gene expressed highly about 16days of embryo stage, then decreased as chest muscle after birth.Pax-7 gene in chest and leg muscle expressed similary, and both expression peaks appearanced in 8-10 weeks age.