Estimation Of Genetic Parameters And Effect Of Candidate Gene TRIB3 For Growth Traits In Large White Pigs

Genetic parameter estimation is a fundamental condition for the smooth development of breeding work,and is essential for estimating genetic progress and optimizing breeding plans.This study takes 19406 American white pigs from the national core breeding pig farm(Yunnan Fuyuefa Livestock and Poultry Breeding Co.,Ltd.)as the research object,estimates the phenotypes and genetic parameters of their main growth traits,and explores the molecular genetic background and molecular genetic mechanisms of the main growth traits of American white pigs.At the same time,using TRIB3 gene as a candidate gene for growth traits,we will further explore the effect relationship between TRIB3 gene and growth traits in large white pigs,search for gene loci with breeding value,and provide certain reference and basis for optimizing the breeding plan of large white pigs.The main results are as follows:(1)Seasons had no significant effect on 100 kg live backfat thickness(BF)and 100 kg live eye muscle area(LEA)(P >0.05),while years and genders had significant or extremely significant effects on the age of 30 kg body weight days(D30),100 kg body weight days(D100),30-100 kg average daily gain(ADG),100 kg live backfat thickness(BF),100 kg live eye muscle area(LEA),and 30-100 kg feed to weight ratio(FCR)(P<0.05 or P <0.01).The heritability of six growth traits were 0.174,0.283,0.348,0.426,0.286,0.412,respectively;The genetic correlation between the age of reaching 100 kg body weight and the average daily gain of 30-100 kg is strong,with a correlation coefficient of-0.8328;The phenotypic correlation between the age of reaching 100 kg body weight and the average daily gain of 30-100 kg is strongest,with a correlation coefficient of-0.843.(2)A total of 10 SNP loci were detected in the TRIB3 gene,of which 2 were located in exon 2 and 8 were located in exon 4.Among them,except for the C132 T site that did not reach the Hardy Weinberg equilibrium state(P <0.05),all other sites were in the Hardy Weinberg equilibrium state(P >0.05).The genetic diversity of the 10 SNP loci is relatively rich and all belong to moderate polymorphism.The TRIB3 gene polymorphism is significantly associated with most growth traits in large white pigs(P <0.05).The C132 T locus TT genotype has a significant effect of shortening the age of up to 100 kg body weight and reducing daily gain by 30-100 kg(P <0.05);The AA genotype at G16 A locus significantly reduced the feed to weight ratio of 30-100 kg(P <0.05);The heterozygous genotypes at T146 C,A10G,and A11 G loci have the largest 100 kg live eye muscle area;The CC genotypes at T160 C,T196C,and T490 C loci can significantly shorten the age of100 kg body weight and increase the average daily gain of 30-100 kg in large white pigs(P<0.05).There was a significant correlation between different haplotype combinations in the daily weight gain of 30 kg,100 kg,30-100 kg,100 kg live eye muscle area,and 30-100 kg feed to weight ratio of large white pigs(P <0.05 or P <0.01).In summary,the TRIB3 gene has a significant effect on some growth traits in large white pigs,but the effect of TRIB3 varies among different traits.