Porcine SPP1 Gene Polymorphism Association with Phenotypic Traits in the Landrace × Jeju (Korea) Black Pig F2 Population

This study examined polymorphisms of the secreted phosphoprotein 1 (SPP1) gene and its association with growth and carcass traits in the F(2) population of the crossbred Landrace × Jeju (Korea) Black pig. The authors detected the presence/absence polymorphisms of short interspersed nuclear element in the SPP1 intron 6 of the population; they then designated the longer fragment as allele A and the shorter one as allele B. The SPP1 A/B heterozygous pigs evidenced significantly heavier body weight at birth and on days 21 and 70, and a higher level of average daily gain during the early developmental period than was seen in the A/A and B/B homozygous pigs (P < 0.05). Further, the SPP1 A/B heterozygous pigs evidenced significantly greater body length, less backfat thickness measured at three different sites, and larger loin muscle area than the homozygotes (P < 0.05). On the other hand, the levels of late average daily gain, 140th-day body weight, and marbling score were not significantly associated (P > 0.05). The results of this study reveal faster growth rate and differences in pig productivity according to genotypes of the SPP1 gene. These findings demonstrate that SPP1 genotypes may effectively function as molecular genetic markers for the improvement of Jeju Black pig-related crossbreeding systems.