Association of a melanocortin 4 receptor (MC4R) polymorphism with performance traits in Lithuanian White pigs

The melanocortin 4 receptor is expressed in virtually all brain regions of mammals and plays an important role in energy homeostasis. Polymorphisms in this gene may thus be related to growth and obesity. In pigs, a non-synonymous polymorphic site was described (Asp298Asn) and demonstrated to affect cAMP production and to alter adenylyl cyclase signalling. Association studies revealed significant linkage of this mutation with production trait in pigs. In this study, 207 Lithuanian White pigs were genotyped at the MC4R locus and analysed on relationships between genotype and breeding values for several performance traits. The observed allele and genotype frequencies did not deviate significantly from Hardy-Weinberg equilibrium (wildtype allele 0.59; mutant allele 0.41) and are comparable with those described in other Large White populations. The mutant Asn298 allele of the MC4R gene was significantly associated with increased test daily gain, higher lean meat percentage and lower backfat thickness. There was a trend towards an improved feed conversion ratio (p = 0.065) in animals with the mutant allele whereas no significant effect was found on lifetime daily gain. These results indicate that the MC4R polymorphism should be integrated in selection programmes in the Lithuanian White to improve carcass composition.