Differential Analysis Of Methylation Profiles Of Abdominal Adipose Tissues In Fat And Lean Chickens By Bisulfite Sequencing

Too much fat deposition is a key issue that needs to be addressed in the broiler production process.Excessive fat in the abdomen will not only reduce feed utilization and chicken flavor,but also hinder the processing of chicken meat.It will also cause certain environmental pollution,greatly reduce consumer satisfaction and the economic benefits of producers.Therefore,reducing excessive fat deposition has important economic value.In this experiment,we studied the abdominal fat tissue of Guangxi three yellow chicken broiler line N409,used for the BS-Seq to analyze the methylation patterns of the chicken’s abdominal fat tissue,and discussed the differences of the methylation patterns of obesity and lean chickens.In order to further study the mechanism of genetic regulation of abdominal fat deposition in chickens,we attempted to find differentially methylated genes that affect abdominal fat deposition.The main results are as follows:(1)In this study,we obtained the global genomic methylation profile in abdominal fat tissue of high quality chicken by BS-Seq.(2)On the genome,the total methylation levels of cytosine in the fat(H)and lean(L)groups were 2.45% and 2.46%,respectively.In the H group,the sites of 49.50% CG,0.12% CHG,and 0.13% CHH were methylated,and the sites in the L group were 49.53% CG,0.08% CHG,and 0.10% CHH,respectively.The proportion of CG methylated cytosine in abdominal fat tissue in group H was 2.14% lower than that in L group,while the ratio of methylated cytosine in CHG and CHH types was 1.5 times than that in L group,indicating that H group and L group had different Genome-wide methylation characteristics.(3)A total of 729 DMRs were obtained from the BS-Seq and 169 of them were mapped to the Gene Body.Compared with group L,methylation levels of 71 DMRs in group H were higher than those of group L,and methylation levels of 98 DMRs were lower than that of group L.The KEGG analysis of differentially methylated genes is enriched in many fat metabolism related pathways,such as FoxO signaling pathways,glycerol lipid metabolism,PPAR signaling pathways,etc.(4)Through the comparison of methylation levels,we have discovered the candidate genes that may regulate the deposition of abdominal fat,such as PTRF,TAF8,EDYM2,B3GNTL2,EDSC,DYNLRB2,MIR103A1,HEP21,TRIM7.1,C17H9ORF9,etc.(5)The mRNA relative expression of PTRF was significantly different in the abdominal fat tissue of group H and group L.It is speculated that DNA methylation in the promoter region of PTRF may affect the expression of its own genes and regulate fat deposition in chickens.