Polymorphism of Selected Microsatellite Markers against Breeding Performance Indexes of Polish Large White and Polish Landrace Sows

The study aimed to analyze 12 microsatellite markers located in the areas of quantitative trait loci related to litter size in 82 sows, including 45 Polish Large White and 37 Polish Landrace sows, kept on a farm in southwest Poland. Breeding documentation provided data on the total number of piglets born per litter and the numbers of live-born, stillborn and weaned piglets; the corresponding percentage values were also calculated. DNA isolation was performed from 15–20 hairs taken from live animals, and the markers used in the research were divided into four multiplexes. The influence of genotype at a given locus on the reproductive traits was analyzed only for genotypes represented by at least five animals. The results of the analyses for all the sows (treated as the maternal component and not as distinct breeds) showed statistically significant ( p ≤ 0.05) differences between the genotypes and the values of the analyzed traits for markers S0008 , SW160 , SW245 , SW714 , SW1125 and SW2411 . Among these markers, the breed-dependent analysis also showed significant differences in the Polish Large White breed for markers S0008 , SW160 and SW1125 , and in the Polish Landrace breed for SW245 . Additionally, the breed-dependent analysis found significant differences in markers SW903 and SW1808 for the Polish Large White sows, and S0064 , SW472 and SW903 in Polish Landrace sows. SW903 was the only marker for which differences in the analyzed reproductive traits differed between genotypes in both breeds (still analyzed separately), although in terms of different traits. The above results indicate the usefulness of microsatellite markers in researching the differentiation of litter size indicators. Although both breeds belong to the maternal component, they showed significant differences in terms of markers. This may suggest difficulties in finding universal (that is, working well for various breeds of the maternal component) markers, indicating the need to look for breed-specific markers, something that calls for further research into numerous animals.