Effects Of Ceratoides And Alfalfa On DNA Methylation Of Longissimus Dorsi In Sheep

DNA methylation is an important form of epigenetic regulation that regulates gene expression and tissue development.The type of feed can affect the structure of rumen microflora and the expression of genes related to the c AMP pathway.However,the effect of feed type on DNA methylation in the longissimus dorsal of sheep is unknown.In this study,we used Whole-genome bisulfite sequencing(WGBS)to compare the effects of two diets,high fiber and low protein(ceratoides)and low fiber and high protein(alfalfa),on DNA methylation in sheep longissimus dorsal,to understand and investigate the relationship between differences in DNA methylation levels and genes of pathways related to glycolipid metabolism,and to compare the nutrient composition and fatty acids of sheep longissimus dorsal fed on the two diets.This study has drawn the following conclusions:1.DNA methylation sequencing of the longissimus dorsal of ceratoides and alfalfa-fed sheep yielded approximately 291 M Clean reads per group.a total of approximately 3.0% of the genomic loci in each group were methylated.Approximately293.17 M Clean reads were generated for the ceratoides twin lamb methylation group and290.10 M Clean reads were generated for the alfalfa twin lamb methylation group.Longissimus dorsi DNA methylation was present in three forms,CG,CHG and CHH.The percentages of the three types of methylation sites in the whole genome were 90.21%(CG),2.12%(CHG),and 7.67%(CHH)for the ceratoides group and 88.56%(CG),2.50%(CHG),and 8.93%(CHH)for the alfalfa group,respectively.A total of 1945 CG differentially methylated regions(DMR)and 1471 CG differentially methylated genes(DMG)were identified in the two groups.2.368 differentially expressed genes(DEG)and 487 differentially expressed transcripts were found in longissimus dorsiof sheep fed with ceratoides and alfalfa.There were 11 overlapping genes between DEGs and DMGs.Among the 11 genes,the expression of FKBP5 and FOXO1 was significantly different between the two groups(P<0.05).FOXO1 regulates gene expression in c AMP and glycolysis/gluconeogenesis pathways.DMGs were enriched in 274 KEGG pathways,and glycolysis/gluconeogenesis and FOXO pathways were significantly enriched.The expressions of HOMER1 and FOXO1 in ceratoides group were significantly higher than those in alfalfa group(P<0.05),and the up-regulation of HOMER1 and FOXO1 in ceratoides group was significantly correlated with hypomethylation.3.Nutrient composition and fatty acid analysis of the longissimus dorsal of sheep fed ceratoides and alfalfa diets were found.The ceratoides diet increased the water content in the lamb(P<0.05).The alfalfa diet increased the fat content in the longissimus dorsal(P<0.05).At the same time,ceratoides feed increased the content of the essential fatty acids linoleic acid and arachidonic acid,which are beneficial to humans,in the longissimus dorsal of lambs.In conclusion,feed type can affect DNA methylation levels in the longissimus dorsiof sheep.FOXO1 can regulate glucose metabolism,c AMP and glycolysis/gluconeogenesis pathways.And FOXO1 can stimulate glucose production by activating specific gluconeogenic target genes through inducing PDK4 expression in muscle and also regulating FKBP5 activity.Ceratoides feed increased the moisture content of lamb for better meat quality,and alfalfa feed can increase the fat content in the longissimus dorsi.However,further analysis revealed that the content of linoleic acid and arachidonic acid,which are essential fatty acids with beneficial effects on human health,was significantly increased in the longissimus dorsal of lambs fed ceratoides feed compared to alfalfa feed.The results of this study may provide new ideas and insights for better understanding the regulation of muscle energy metabolism and future feed development for the production of functional meat for animal husbandry.