Effects of hydroxy‐delta‐5‐steroid dehydrogenase, 3 beta‐ and steroid delta‐isomerase 1 polymorphisms on fat androstenone level and gene expression in D uroc pigs

Summary A high level of androstenone in porcine adipose tissue is a major factor contributing to boar taint. P orcine hydroxy‐delta‐5‐steroid dehydrogenase, 3 beta‐ and steroid delta‐isomerase 1 ( 3β‐ HSD , also known as HSD3B1 ) plays a key role in the hepatic metabolism that catalyzes androstenone to β‐androstenol. Therefore, 3β‐ HSD is a candidate gene for boar taint. This study aimed to investigate functional 3β‐ HSD polymorphisms in D uroc pigs. We found eight single nucleotide polymorphisms ( SNP s) in the full‐length porcine 3β‐ HSD . Four of the SNP s had restriction enzyme sites, and we genotyped them in 147 uncastrated male D uroc pigs using a polymerase chain reaction–restriction fragment length polymorphism method. Pigs with the GG genotype at the g.165262G>A locus ( SNP 5) had significantly lower androstenone levels than did those with other genotypes ( P  =   0.030). SNP 5 also was associated with differences in 3β‐ HSD mRNA levels: pigs with the GG genotype had higher levels than those with other genotypes ( P  =   0.019). The SNP 5 polymorphism could affect the hepatic catabolism of androstenone and consequently impact androstenone accumulation in the adipose tissue. Therefore, SNP 5 in the 3β‐ HSD of D uroc pigs could be a useful selective marker for decreasing boar taint.