Received: 02-05-2019 / Accepted: 30-09-2019
Litter size of pigs is an important economic trait, but its heritability is relatively low,at approximately 0.1. In addition, litter size trait can only be measured on female pigs at mature age. Therefore, genetic improvement by phenotypic selection is less effective, and at slow rate. In previous literature, it is found that ESR and PRLR genes are two QTLswith large effects on litter size in pigs. Of the two alleles A and B at ESR locus, allele B shows a positive effect on the litter size trait,while of the two alleles A and B at PRLR locus, allele A is benefical to the trait. Landrace and Yorkshire, which are imported, are two major breeds in Vietnam. The current study aimed to evaluate genetic structures of ESR and PRLR genes in two pig populations of Landrace and Yorkshire reared at the Dabaco nuclear breeding pig company, and thus examine the effects of ESR and PRLR genes on reproduction traits of the two pig populations. It was found that all three genotypes,AA, AB and BB at ESR and PRLR loci,were present in both the populations of Landrace and Yorkshire pigs. At ESR locus, allele frequency of B in the Landrace population (0.184) was lower than in the Yorkshire population (0.413). The frequency of homozygous genotype BB was 0.041 for the Landrace population and 0.655 for the Yorkshire population. At PRLR locus, allele frequencies of A and B were quite similar for the two populations. Allele frequency of A was 0.483 for Landrance and 0.516 for Yorkshire. Allele frequency of B was 0.517 for Landrance and 0.484 for Yorkshire.
