The effect of point mutation in RYR1 gene on the semen quality traits in boars of Large White and Landrace breeds

The experiment involved 34 boars of Large White (LW) and 25 Landrace (L) breeds reared at three A.I. stations in the first year of their use in breeding of known RYR1 genotypes (NN and Nn). Altogether 2772 ejaculates were examined. The results corroborated the existence of significant associations of RYR1 genotypes with all semen quality parameters under study. Significant effects were demonstrated for the effects "breed", "RYR1 gene x breed interaction" and "A.I. station x month x year interaction". If compared with heterozygous individuals, homozygous boars with NN genotype produced the semen with larger volume (P less than or equal to 0.05), highly better motility (P less than or equal to 0.001), lower sperm concentration (insignificantly), lower number of abnormal spermatozoa (P less than or equal to 0.01) and higher number of A.I. doses (P less than or equal to 0.001). When classified into individual genotype and breed categories, a significantly smaller semen volume and higher sperm concentrations (P less than or equal to 0.001) were found out in homozygous LW boars with the NN genotype than in those with the heterozygous genotype Nn. On the other hand, among the boars of L breed, NN boars produced semen with larger volume (P less than or equal to 0.05) and lower sperm concentrations than those with the heterozygous genotype Arn (P less than or equal to 0.001). In other parameters under study the same tendencies were observed in both breeds. Boars with homozygous NN genotypes showed significantly better parameters of semen quality than the heterozygous (Nn) ones.