Reproductive performance and its association with ESR, PRLR, FSHB genes in indigenous “I” pigs

Abstract

Improving the reproductive performance of sows plays an important role in the pig industry, and it applies not only to commercial pigs but also to indigenous pigs. In this study, the polymorphisms of three genes, namely estrogen receptor (ESR), prolactin receptor (PRLR), and follicle-stimulating hormone beta subunit (FSHB) in the “I” pig population were investigated, and their associations with reproductive performance were evaluated. Ear tissue samples were collected from 151 fattening pigs and 126 sows across breeding farms in Vietnam for polymorphisms of the ESR, PRLR and FSHB genes. Three genotypes (AA, AB, and BB) were detected at the ESR T1665G and FSHB T212C loci, whereas the AA genotype was not observed at the PRLR G1789A locus. Consequently, genotype frequencies of ESR and FSHB were in Hardy-Weinberg equilibrium, while PRLR deviated significantly (P < 0.001). The ESR genotypes and parity showed no significant effects on the reproductive traits. The PRLR G1789A polymorphism showed a significant effect only on BWW, with sows carrying the BB genotype exhibiting more favorable values than those with the AB genotype. However, most of the traits differed across years, except age at first mating (AFM) and farrowing interval (FRI). The FSHB genotypes significantly affected reproductive performance, excluding AFM, age at first farrowing (AFF), FRI, and piglet birth weight (BWB). Sows with the FSHB^AA genotype had a higher number of total piglets born and greater piglet body weight at birth and weaning than those carrying FSHB^AB. These findings indicate that the FSHB^AA genotype may serve as a useful genetic marker for enhancing reproductive traits in the endangered “I” pig population.