Study On Effects Of ESR And FSHβ On Prolificacy In Sows

PCR-RFLP method was adopted to examine the genetic variety of genes ESR and FSHβ in 5 pig populations ( Landrace and Large White from the farm of Zhenghong; Landrace, Large White, Duroc from the farm in the agriculture institute of Yiyang). Frequencies of the genes and genotypes were calculated according to the experimental results. Gathering the litter size data of examined pigs (including the total number of born and the number of born alive), analyze the effects of them on prolificacy. The effects of single gene and their combined genotypes were considered. The main result is as follows:(1), In different variety, frequencies of the allele A and B in gene ESR are different, so do the frequencies of its genotypes. Among alien variety tested, the frequency of allele B and the frequency of genotype BB are relatively low. For example, in this research, the frequencies of allele B in Large White and Landrace is lower than 0.5.(2), In breeds tested, the frequency of allele A and the frequency of genotype AA in FSHβ is relatively low. For example, in this research, the frequency of allele A is lower than 0.4 and the frequency of genotype AA is lower than 0.1.(3), ESR is one main gene which controls the trait prolificacy in pigs, its advantageous allele is allele B. No matter in TBA and NBA, genotype BB is higher than AA and AB, while genotype AB is higher than the AA type. In this research, mean TNBs of genotype AA, AB, BB in Large White are successively 10.030 , 10. 117, 10. 581, and mean NBAs are successively 8.590 , 8.908, 9.047.(4), The effects of every genotype in FSHβ is successively BB, AB, AA from high to low. For example, in this research, mean TNBs of genotype AA, AB, BB for FSH β in Large White are successively 9- 610,10- 193, 10. 444, and mean NBAs are successively 8.570,8. 866, 8. 935; in Landrace the similar conclusion is obtained, too. It is one main gene controls the trait prolificacy in swine and its advantageous allele is allele B.(5), The effects of combined genotypes of ESR and FSHβ have no obvious law. Its genetic effects on prolificacy are not simply the multiplications of every genotype. But its effect of combined genotypes is higher than the effect of individual genotype. It offers the basis for its application in production.(6), Age is one important factor influencing of prolificacy, the TNB of firstborn is less than the TNB of the still-born, so does in NBA(7), The trait prolificacy is low in hereditability and is sex-limited. The progress achieved by normal selection methods is not obvious. In this research the effects of ESR and FSHβ on prolificacy is proved to be obvious, and they are abundant in polymorphism. So we can use them as molecular marker in MAS in order to improve the level of prolificacy.