Polymorphism Of Hormone-sensitive Lipase Gene And Growth And Differentiation Factor 8 And Their Correlation With Lean Meat Percentage In Two Guizhou Native Pig Breeds And Large White × Landrace Crossbreds

Raising lean meat percentage of the pig is one of the urgent challenges to livestock development.With huge pork consumption,to raise lean meat production has ever been playing an important role in pig production in China.It is of great significance to raise the lean meat percentage,using molecular genetics technology,for Guizhou native pigs which is belonged to fat-type pigs.A slaughter trial was conducted to analyze the traits related to lean meat percentage of Nuogu,Luobo,and Large×York crossbred pigs;and the polymorphism of gene related with lean meat percentage was assessed by PCR-RFLP molecule marker and gene clone techniques to obtain the accessory molecule markers related with lean meat percentage.In trial 1,Nuogu,Luobo,and Large white×Landrace crossbred pigs were slaughtered to determine their difference of lean meat percentage.There is significant difference in lean meat percentage among Nuogu,Luobo,and Large white×Landrace crossbred pigs(44.0: 41.4:66.7%,P＜0.05).The lean mean percentage is positively related with loin eye area (r=0.539) and is negatively related with backfat thickness(r=-0.558).The objective of trial 2 was conducted to study the polymorphism of HSL and GDF-8 genes in Nuogu,Luobo,and Large white×Landrace crossbred pigs by PCR-RFLP and gene clone techniques.The polymorphism of HSL and GDF-8 genes was adequate in Nuogu, Luobo,and Large white×Landrace crossbred pigs.The B allele of HSL gene and N allele of GDF-8 gene were higher in Large white×Landrace pig(91.67;30%) than that of Nuogu(40; 10%)and Luobo pigs(10.53;16%) and belonged to protogene of lean meat,howover, fat-type pig breeds of Nuogu pigs(60;90%) and Luobo pigs(89.47;84%) have more A allele of HSL gene and M allele of GDF-8 gene than Large white×Landrace pig(8.33;70%). Valine was mutated to be isoleucine due to the presence of G433A in HSL gene.The SNPs were identified at C42T and G71A in exon 3,respectively,but C⁴²â†’T does not change coded Leu for silence mutation in N allele and G⁷¹â†’A makes Arg→Gln at 24^th amino acid in some crossbreds in N allele of GDF-8,C⁴²â†’T located domain effect the role of GDF-8.From the above-mentioned results,it is suggested that the B allele of HSL gene and N allele of GDF-8 gene may be a marker gene for the lean meat percentage.