Polymorphism of Insulin-like Growth Factor Binding Protein-4 Gene in 17 Pig Breeds and Its Relationship with Growth Traits

Insulin-like growth factor binding protein-4 (IGFBP-4) is a member of the IGF super family, and regulates the action of IGFs. The polymorphism of porcine IGFBP-4 gene in 17 pig breeds (total n = 570) was detected by PCR-SSCP, and alleles A and B were detected. In these pig breeds, it was found that exotic pig breeds carried high frequencies of allele A, while Chinese native pig breeds carried high frequencies of allele B. The role of porcine IGFBP-4 was investigated in 172 F2 offspring of a Lantang×Lantang population. Forty eight growth traits were recorded for analyzing the association between IGFBP-4 gene polymorphism and quantitative performance traits. In this resource family, pigs with AA genotype had higher fore-body weight, bone weight of mid-body, bone weight of rear-body, fore-leg weight and rear-leg weight than those pigs with BB genotype (p<0.05); while pigs which carried BB genotype had higher back-fat thickness at C point and lard weight than those pigs with AA genotype (p<0.05); pigs with AA genotype had higher body weight than those with BB genotype; for meat quality traits, pigs with AA genotype had higher meat color than those of BB genotype (p<0.01), and pigs with BB genotype had higher marbling than those of AA and AB genotypes (p<0.01 and p<0.05, respectively).Based on these results, it is necessary to do more studies on IGFBP-4 before using the IGFBP-4 locus for the application of marker-assisted selection programs. (