Effect of EGF, AREG and LIF genes polymorphisms on reproductive traits in pigs

The aim of our study was to determine the associations between mutations in the EGF, AREG, LIF genes and the reproductive traits in pigs. We examined sows of two Polish breeds, which are used as a dam line in Polish breeding: Large White and Landrace. The reproductive traits investigated were: number of piglets born alive (NBA), number of alive piglets on 21st day (N21), age of sows at first farrowing (AFF) and interval between two successive litters (IBTSL). Polymorphisms in AREG and LIF (C4950G) genes were detected by using PCR-RFLP methods, with restriction enzymes StyI and DraIII, respectively, in EGF gene by using PCR method, while C6988T in LIF gene by PCR-SSCP methods. The statistically significant differences were found at the locus EGF: sows with BB genotype showed higher number of piglets born alive (NBA) and higher number of alive piglets on 21st day (N21) (P < 0.01 and P < 0.05) when compared to the other genotypes. At the LIF1 locus sows of AA genotype had higher number of NBA (P < 0.01) when compared to BB genotype, and at the LIF3 sows of BB had better results for this trait when compared to AA and AB genotype (P < 0.01 and P < 0.05). In our study, we obtained also statistically significant results for association between AREG gene and reproductive traits. In parities 2 to 4, statistically significant differences were observed between sows of A1A1 and A1A2 genotype of the AREG gene for NBA (P < 0.05) and between AA and BB genotypes of the LIF1 gene for NBA and N21 (P < 0.01 and P < 0.05).