Molecular Mechanisms Of Phenotypic Inheritance For Fatty Liver Induced By High-fat Diet In Chickens

Fatty liver,also known as fatty liver syndrome or fatty liver hemorrhagic syndrome,is a metabolic disease which is likely caused by nutritional,hormonal,environmental and genetic factors.It is common in laying hens with an incidence of 5%-30%.Fatty liver is often ignored because its symptoms are not as obvious as those of infectious diseases,but in actual production,it is common in both laying hens and broiler breeders.Compared with infectious diseases,the mortality of fatty liver is lower.Nevertheless,it can cause decreased egg production,fertilization rate and hatching rate,which lead to economic losses in the poultry industry.Unlike in mammals,lipids and lipoproteins are mainly synthesized in the liver in poultry.Fat metabolism of liver is in a dynamic balance under physiological conditions.Lipid homeostasis is destabilized when disorders of metabolic pathways occur,such as lipid absorption,lipid synthesis,?-oxidation and lipoprotein transport,during which lipid accumulates excessively in the liver,thereby leading to fatty liver,but the pathophysiological mechanisms leading its development of fatty liver remain unclear.Environment,genetic factors and their interactions play important roles in growth and development,phenotypic generation and pathogenesis.Epigenetics is a science that studies the interactions between gene factors and environment,and DNA methylation is an important part of epigenetic modification.DNA methylation regulates gene expression by affection the function of individual promoters and enhancers,or affection the whole chromosome and genome level,thereby influence the phenotype of the offspring,at the same time this effect can be passed on to offspring by cell division.At present,the researches on fatty liver in chicken are mainly focused on etiology and prevention,and molecular mechanism of fatty liver is largely unknow.In this study,the fatty liver model induced by high-fat diet was used,at the same time the parent genetic group,the parent genetic group and the control group of fatty liver were constructed,and RNA-seq and whole genome DNA methylation analysis were carried out between the experimental group and the control group when the phenotypic genetic patten of fatty liver was investigated,and then candidate genes and methylation sites of fatty liver were scteened by bioinformatics and group analysis.This results uniquely revealed that acquired fatty liver in cocks can be inherited.The genes related to fatty acid metabolism(ACACA,FASN,SCD,ACSL5 and FADS2),lipid metabolism(FABP1 and APOA4)and glucose metabolism(ISR4 and ME1)participated in regulation for phenotypic inheritance of fatty liver induced by high-fat diet in Jingxing-Huang chicken.In addition,the DNA methylations of ACACA and SCD regulate its expression,and then involve in regulating phenotypic inheritance of fatty live.The results will provide basis for reveal the pathogenesis of fatty liver and disease resistant breeding in chicken.