The aim of the experiment was to use the DNA mutations in the PRLR and LEP genes to determine associations between the genotype and litter size in Polish Large White x Landrace sows. Reproductive traits investigated were: total number of piglets born (TNB), number of piglets born alive (NBA) and number of piglets weaned. The polymorphism in PRLR and LEP genes was detected using the polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) method, with specific primers and the restriction enzymes AluI and HinfI respectively. Two different alleles of PRLR and LEP gene were identified: alleles A (0.62) and B (0.38) of the PRLR gene and alleles C (0.10) and T (0.90) of the LEP gene. The relationships between the PRLR and LEP genotypes and TBN, NBA and NW were analysed. The analysis showed, in first parity sows, statistically significant (p < or = 0.01) differences between sows carrying different PRLR genotypes. In later parities, sows with the AA genotype still had the largest litter size compared with AB and BB sows, but the difference was statistically not significant. Analysis of the interaction PARITY x PRLR showed small and statistically not significant differences. The analysis of relationship between different LEP genotypes and TNB, NBA, NW showed small and statistically non-significant differences.

The objective of the present study was to analyze the level of intramuscular fat (IMF) in loin (musculus longissimus dorsi) and ham (musculus semimembranosus) and the level of subcutaneous fat in these cuts depending on breed, age and the expression level of FABP3 and LEPR genes. The results obtained showed that only the breed influenced on the level of both intramuscular and subcutaneous fat to the same extent (P ≤ 0.001). The age of animals had an effect on fat content of the cuts (P ≤ 0.001) and to a lower extent on the level of IMF in both muscles (P ≤ 0.05). We confirmed highly significant effect of breed and age on the LEPR mRNA abundance—the expression of the this gene increased significantly (P ≤ 0.01) with age and the highest expression was found for the Puławska breed in m. longissimus dorsi and for the Polish Landrace breed in m. semimembranosus. We observed the high correlations between the transcript level of the LEPR gene and the fat content of individual cuts (P ≤ 0.01). The expression level of FABP3 gene influenced the level of IMF (P ≤ 0.01), but not the level of subcutaneous fat in loin and ham.

SummaryProlactin reeeptor gene (PRLR), which is localized on chromosome 16 in pigs, is a candidate eene marker Ihr XÄ tra V he eXPen ' me !; t WaS aim6d l° deteCt the DNA mutatio " s !" that gene and SÄJ relations between the genotype and some reproduetive traits in Polish Landrace pigs 207 sows and 8 boars from pedigree herd were studied. The polymorphism in PRLR gene locus was detec Jusing TCR^L Method w ,h specific primers and restriction enzyme Alul. Two different alleles were identified-?S 3 T frequency of PRLR» was estimated at 0.44 and PRLR» -0,56. In the stud d popula on ofZ'fiSc"ie S of tZZT * B T ?» W r 0247> °' 386 and °3 67 ' '«Pectively. The relations beÄÄSpe and teats number on the left and right body side, total number of teats, number of piglets in the fSttefSe ageat t e first parity were analyzed. All data were transformed from the discrete scfle into the qu i, iv" o e The analysis showed the significant dependencies (P < 0,01) between the number of piglets in the firs litter and geno g^Pe Pr reCeP ' 0r ' Signif,CantI >' W " umbe ' °f Pigl^s characterized the sows carrying AA

The prolactin receptor gene (PRLR), located on chromosome 16 in pigs, is a candidate gene for reproductive traits. The experiment was aimed to detect the DNA mutations in this gene and to find probable relations between the genotype and some reproductive traits in boars. The polymorphism in the PRLR gene was identified by PCR-RFLP method using specific primers and the restriction enzyme AluI. In total 229 boars of various breeds were genotyped. The frequency of allele A was estimated at 0.62 and allele B at 0.38. Genotype AA was found at a frequency of 0.45, AB at 0.35 and BB at 0.20. We found associations between PRLR genotype and ejaculate volume, sperm concentration, percentage of live sperm, and number of live sperm in the ejaculate (P < 0.01).

The aim of this study was to estimate the relationship between prolactin receptor (PRLR) gene polymorphism and litter size in pigs of synthetic line 990 (n = 374). Prolactin receptor gene variants were determined by PCR-RFLP method. It was demonstrated that the analyzed polymorphism had significant influence (P ≤ 0.05) on reproduction traits in the first parity.