Abstract：Peroxisome proliferator-activated receptor-γ coactivator-1 alpha (PGC-1α) has been a hot studying spot gene in meat quality traits of livestock because of its prominent role in regulation of muscle fiber type switching. To study the expression profile of PGC-1α gene in 2 phenotypically distinct muscles between 2 chicken breeds at early growing stage, qRT-PCR and Western blot were used to detect the mRNA and protein expression of PGC-1α gene at 0, 1, 3, 5, 7 and 9 weeks in soleus and extensor digitorum longus between Qingyuan Partridge chicken (slow-growing chicken breed) and Recessive White chicken (fast-growing chicken breed). The results showed that the expression of PGC-1α mRNA of the 2 muscles declined firstly, then increased following by decreasing, and finally increased again. The expression peak of PGC-1α mRNA of all the muscles appeared at 0 week on which the expression levels were significantly higher than that at other weeks (P＜0.05), and the lowest expression in soleus in 2 chicken breeds appeared on 3 week, and the lowest expression in extensor digitorum longus in 2 chicken breeds appeared on 7 week. While the expression of PGC-1α protein of the 2 muscles firstly gradually increased from 0 week to 5 week, then declined from 5 week to 7 week, and increased again from 7 week to 9 week. The expression peak of PGC-1α protein in extensor digitorum longus in Recessive White chicken appeared at 5 week. Although the expression trends of mRNA and protein of PGC-1α gene of the 2 muscles were not identical during early postnatal growth, they were highly muscle phenotype and breed specific. In general, the expression levels of mRNA and protein of PGC-1α gene in soleus were higher than those in extensor digitorum longus of both chicken breeds at the same weeks of age, and the expression of PGC-1α mRNA in 2 muscles was extremely significant difference at 0 week (P＜0.01). The expression levels of mRNA and protein of PGC-1α in Qingyuan Partridge chicken were higher than those in Recessive White chicken at the same weeks of age, and the expression of PGC-1α mRNA in 2 muscles was extremely significant difference at 0 week (P＜0.01). These results indicated that the expression level of PGC-1α might concern with the content of slow muscle fiber in skeletal muscle in chicken, and its function might be closely related to the chicken meat quality. There search provides some valuable clues for understanding the role of PGC-1α in the skeletal muscles in chickens and a theoretical basis for improving the meat quality in chickens.
