Association of the porcine α-lactalbumin gene to growth, carcass, meat quality and reproductive traits

Abstract

α-lactalbumin is one of the two major whey proteins in porcine milk and may be a regulatory factor in milk yield. Pigs from the University of Illinois three generation Meishan x Yorkshire reference family (n=259) were genotyped using a PCR-based test for a polymorphism in the 5' flanking region of the porcine α-lactalbumin gene. The PCR product was digested with Rsal, allowing variation in restriction fragment lengths to be detected by gel electrophoresis. In the F2 generation, two alleles (A and B) had a frequency of 72.2% and 27.8%, respectively and three genotypes were present at the frequency of 48.3% AA, 48.0% AB and 3.7% BB. Growth, carcass, meat quality and reproductive data were analyzed for associations with α-lactalbumin genotype. There was an association between the α-lactalbumin genotypes and age at puberty (P<05) with heterozygous gilts exhibiting first oestrus approximately 2 wk earlier than pigs homozygous for the A allele and more than 4 wk earlier than pigs homozygous for the B allele (AB-142.4 d, SD 9.1; AA-155.5 d, SD 9.0; BB-170.0 d, SD 16.1). Embryo /fetal mortality during the 50 d of gestation was also different among the genotypes (AA=29.2%, SD 4.0; AB=23.9%, SD 4.0; BB=6.9%, SD 8.4; P< .05) and there were trends toward higher post-weaning (second parity) ovulation rates for AA and AB compared with BB animals (15.4 ova, SD 1.31; 16.10 ova, SD 1.30; 11.9 ova, SD 2.01, respectively;.05) were detected between growth and carcass traits and α-lactalbumin genotype. There was trend for an association with the intramuscular fat content of the longissimus (AA=3.67%, SD .50; AB-3.87%, SD .50; BB=5.68%, SD .99; P