The Association Of Polymorphisms Of Four Genes With The Backfat In Songliao Black Swine

As an important economic trait in swine production,backfat thickness(BFT)is the main breeding index in local swine breeding process.For further study of the genetic basis of backfat thickness in songliao black swine,longissimus dorsi muscle tissue and backfat(BF)tissue from 173 pigs were collected,and the MC4 R,HDAC1,LEP and OLR1.Gene polymorphisms were analysed,then the correlation analysis of the polymorphisms effecting the BFT and intramuscular fat content was performed.This research would offer a theoretical basis and molecular markers for decreasing the BFT and increasing increase lean meat percentage.The results were as follows:Different feeding: The BFT of the last rib and lumbosacral area,average BFT in grazing group were significantly lower than those in barn feeding group.Trait analysis:Intramuscular fat content had a strong co-relation with the thickest BF of the shoulder and a significant correlation with the average BFT.In addition,there were strong correlations among the body weight,the thickest BF of the shoulder,the BF of the 6-7 ribs,the BF of the last rib,the BF of lumbosacral area and the average BFT.Polymorphism analysis:The polymorphism sites were detected in MC4 R,HDAC1,LEP and OLR1,which were in Hardy Weinberg equilibrium state.Genetic polymorphisms were moderate,and the genetic variation degree were in the medium level.Association ananlysis showed that 10806 G > A polymorphism in HDAC1 were closely related with the BFT of the 6-7 ribs,the BF of the last rib,the BF of lumbosacral area.9011 T > C and 9012 loci C > A in OLR1 gene were related with intramuscular fat,and 9070 G > A was significant correlation with BFT of different parts.There are no correlation among the polymorphism of MC4 R and LEP,BFT and intramuscular fat.Gene expression:the mRNA level of HDAC1 in 6-7 ribs and the last rib adipose tissue of high BF group were significantly lower than thay of low BF grou-p(P?0.05).The high backfat group's m RNA level of OLR1 in different adipose tissue of high BF group were higher than the low BF group(P?0.05).The mRNA levels of MC4 R,LEP in the two groups had no significant difference(P>0.05).