PROLACTIN RECEPTOR (PRLR) GEN POLYMORPHISM AND ASSOCIATIONS WITH REPRODUCTIVE TRAITS IN PIGS

Abstract

The Prolactin Receptor (PRLR) gene was investigated as candidate gene for swine reproductive traits. 335 sows of 4 genetic groups: Yorkshire (Y), Landrace (L) Duroc (D) and YL were included. The traits studied were: Total Number of Born (TNB), Number Born Alive (NBA), Number of Weaned Piglets (NWP), Litter Weight at Birth (LWB) and Litter Weight at Weaning (LWW). The polymorphism was identified by PCR-RFLP. Allelic frequencies between each genetic group and Hardy-Weinberg equilibrium were tested by chi-square test. The association between PRLR genotypes with reproductive traits was evaluated by a linear model. Additive and dominance effects were estimated. The frequency of A allele was in general 0.46, with variation between genetic groups. D had the highest values for TNB. YL showed the best performance for NBA. AA genotype in D showed the best performance for NWP but no differences were found among genotypes L, YL and L. Differences in first parity were observed between genotypes for TNB, with highest value in BB (10.40 piglets). In general, additive effect per allele A resulted in a negative increase of 2.26 pigs (TNB) and positive of 0.42 kg (LWB) per litter. For TNB and LWB, dominance effect was -2.67 pigs and -0.56 kg, respectively. For LWW, additive in L resulted in -8.37 kg while dominance effect was 8.37 kg.