Polymorphism of Insulin-like Growth Factor 1 Receptor Gene in 12 Pig Breeds and Its Relationship with Pig Performance Traits

Abstract

The polymorphism of insulin-like growth factor I receptor (IGFIR) gene in 12 pig breeds (total n = 593) was detected by PCR-SacII-restriction fragment length polymorphism and allele A (379 bp) or allele B (235 bp and 144 bp) observed. In the studied breeds, it was found that European pigs principally carried allele A, while Chinese native pig breeds principally carried allele B. In addition, the role of pig IGFIR was investigated in 156 Wanbai pigs and 212 Large Yorkshire pigs. Growth related variables including body weight at birth, 2-, 4- and 6-mo of age and backfat thickness and lean percentage estimated by ultrasonography at 6-mo of age were recorded in analyzing the association between IGFIR gene polymorphism and growth traits. AA-genotype pigs exhibited greater (p<0.05) body weights (BW) at birth, 2- and 6- mo of age, but not at 4-mo of age, than those of the BB-genotype in Wanbai and Yorkshire breeds. Moreover, in the Yorkshire breed, AA-genotype pigs had less backfat thickness (p<0.05) and greater lean percentage (p<0.01) than the BB genotyped Based on these results, it is necessary to do more studies on IGFIR before introducing the IGFIR locus into breeding programs.