New polymorphisms and expression of the porcine ghrelin (GHRL) gene in different pig breeds

Growth and development traits are economically important in animal production, especially in pig breeding. Therefore, the porcine GHRL gene is considered as a candidate gene responsible for growth rate and body weight. The aim of our study was to identify new polymorphisms in the GHRL gene in pig. Ten novel single nucleotide polymorphisms (SNP’s) were detected: four substitutions in exons, four in introns and two mutations in promoter region. We evaluated the GHRL mRNA abundance in porcine stomachs (fundus ventriculis) and ghrelin protein concentration in plasma in three breeds: Polish Landrace, Polish Large White and Pietrain. The results showed that transcript abundance of GHRL gene was significantly higher in Polish Landrace than in other two breeds (P<0.05). The mutation c.-93A>G located in the promoter region affected expression of the GHRL gene. The AA genotype animals showed a significantly (P<0.05) higher expression level when compared to AG genotype animals.