Genetic potential of Poltava silver rabbits: G-BLUP evaluation based on polymorphism of MSTN and PGR genes

The article presents the results of the assessment of rabbits of different lines of the Poltava Silver breed using the G-BLUP method with the analysis of the influence of polymorphic variants of the myostatin (MSTN) genes on live weight and progesterone receptor (PGR) on reproductive ability. The indicators of gene diversity in different lines of the Poltava Silver breed for these polymorphisms showed a positive value of the Wright fixation index (Fis), indicating the predominance of heterozygotes for the C and T alleles. Based on the obtained heterozygosity data, Wright fixation indices were calculated. The inbreeding coefficient (Fis) for the genes – MSTN and PGR – showed different distributions between rabbit lines. A higher value of Fis for the MSTN gene indicates a greater deficit of heterozygosity, potentially indicating higher inbreeding effects. On the other hand, a lower value of Fis for the PGR gene means smaller inbreeding effects or that the population is closer to panmixia. Analysis of the influence of the SNP C34T polymorphism in the MSTN gene on the average daily gain of rabbits revealed the following patterns. Heterozygous rabbits with the ST genotype demonstrated higher average daily gains. Their gains were 2.3% higher than those of homozygotes for the C allele (39.0 ± 0.3 g vs. 38.2 ± 0.2 g, p<0.05). At the same time, the average daily gains of homozygotes for the T allele were 2.6% lower than those of heterozygotes for the ST (38.2 ± 0.2 g vs. 39.0 ± 0.3 g, p<0.05). It was found that line 1871817 is the most promising in terms of meat productivity, showing the highest values of BLUP-index (1358), estimated breeding value (EBV, 1.412) and reliability (REL, 1.827), which confirms its high genetic potential. Lines 1847213 and 1832221, on the contrary, have small negative EBV and low REL, which indicates their lower productivity. The G-BLUP method also confirmed the influence of the PGR gene on reproductive traits. Lines 1871817 and 1811231 showed the highest BLUP-index (5.57) for these indicators, which indicates their high potential for transmitting reproductive potential to offspring. In general, the line 1871817 demonstrates high genetic potential both in terms of live weight and the number of weaned rabbits, which makes it a priority in the selection of the best individuals for future breeding programs in rabbit breeding