Gallus gallus Epigenomics

ith the improvement of people's living standards, more and more people pay attention to the meat quality of poultry, which affected by many factors, including breeds and age, tissues and so on. The growth and development process of poultry accompanied with changes in meat quality, such as intramuscular fat content, shear force, drip loss. Many previous studies focused on the distinct breeds; however, little is known regarding its regulatory mechanisms at the epigenetic level in different age stages, such as via DNA methylation. Here, we compared the global wide DNA methylation profiles between young (20 weeks old) and old-aged (55 weeks old) hens to identify candidate genes associated with breast muscle development and meat quality during the growth and development process of chicken using whole-genome bisulfite sequencing. Overall, old-aged hens exhibited higher global DNA methylation levels at the genome level than young-aged hens. A total of 2,714 differentially methylated regions were identified in the present study, which corresponded to 378 differentially methylated genes. In the old-aged groups, several genes related to ATPase activity, lipid metabolism, aging process were found a significantly stronger methylation. The methylation status of three differentially methylated genes was confirmed using bisulfite sequencing PCR. This study revealed the global DNA methylation pattern of chicken breast muscle between different age stages. The hypermethylation of the promoters of ABCA1, COL6A1 and GST1L in old-aged hens may result in the distinct differences of meat quality between different age stages in Gushi hens. The result of our study might contribute to us a better understanding of epigenetic regulation in skeletal muscle development and meat quality of chicken in different age stages.