Abstract：Lipoprotein lipase (LPL) has the function of regulating fat deposition in animals, but its molecular genetic mechanisms is seldomly studied in local mini-pig (Sus scrofa) breeds. In order to understand the function of gene LPL and reveal its effects on meat quality traits in Congjiang pigs. In this study, the CDS region of LPL gene was cloned by RT-PCR from Congjiang pigs, the physical and chemical properties as well as structure characteristics of LPL protein was predicted using bioinformatics softwares. The genotype of AfaⅠlocus of intron 5 in Congjiang pigs was tested by polymerase chain reaction-restriction fragment length polymorphism technique (PCR-RFLP). Meanwhile, the expression profile of LPL gene was investigated by qRT-PCR and their association with content of intramuscular fat and activities of LPL in dorsal muscles of different stages Congjiang pigs were analyzed. The results showed that the CDS of LPL gene was 1 437 bp encoding a stable, hydrophilic protein with 478 amino acids and a PLAT/LH2 domain. There was high amino acid homology of LPL among different breeds of pig, the amino acid sequence of LPL of Congjiang pigs had similarity of 99.8% with Norwegian Landrace and Luchuan pigs, the lowest homology with Guizhou baixiang pigs was 99.2%. PCR-RFLP results showed that the AfaⅠlocus of the LPL gene have 3 genotypes in Congjiang pigs, i.e. CC, CG and GG, and the CG was dominant genotype. The allele frequencies of C and G at AfaⅠlocus were 0.350 5 and 0.649 5, repectively. The Congjiang pig population investigated was at Hardy-Weinberg equilibrium in this polymorphic sites. The skin thickness of CC genotype was significantly higher than that of CG genotype at AfaⅠlocus in Congjiang pigs (P＜0.05). Furthermore, the backfat thickness, lion eye area and intramuscular fat content of CC were also higer than those of other genotypes (P＞0.05). qRT-PCR results suggested that the expression level of LPL gene in the dorsal muscles of Congjiang pigs at different stages was decreased first and then increased, the correlation analysis indicated that there was a significant correlation between LPL mRNA expression and intramuscular fat content (P＜0.05). In conclusion, the LPL gene might play an important role in the IMF deposition of Congjiang pigs, this study could provide a theoretical basis for the follow-up analysis of structure and function of LPL gene in Congjiang pigs.
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