Pedigree Construction Of Two Pig Herds And Preliminary Study On The Effects Of Inbreeding And Parity On Immunity Of Wannanhua Pig

The level of immunity is not only closely related to self-resistance,but also affects the reproductive performance of sows.Affected by the invasion of African swine fever,the non-standard management system of pig farms and the disordered sources of breed-ing pigs,there are currently problems such as missing or wrong pedigrees in local pig farms in Anhui,which will increase the risk of pig inbreeding.The purpose of this study was to preliminarily study the effect of different parities on the immune level of pigs,identify the genetic relationship between different individuals,and provide reference for the protection and utilization of local pig resources in Anhui.In this work,the Anhui local breeds of Wannanhua pigs and Yixian black pigs were selected as the research objects,and the 50K gene chip data was used to identify the kinship and detect the Runs of Homozygosity（ROH）in Wannanhua pigs,calculate the identity by state（IBS）distance matrix,G matrix,inbreeding coefficient F_ROHof Wannanhua pig,analysis the principal component and carry out the gene ontology（GO）terms and KEGG pathway by the high frequency region of ROH in Wannanhua pigs.At the same time,the immune indexes such as interleukin-10（IL-10）,interferon-γ（IFN-γ）and immunoglobulin G（IgG）in the serum of Wannanhua pig were detected.In addition,a set of 8 STR was used to conduct the paternity identification and genetic diversity analysis of Yixian black pig.The results were as follows:1.The serum levels of IL-10,IFN-γand IgG of Wannanhua pig all decreased after primiparous.When the parity was greater than or equal to 1,the levels of IFN-γ,IgG and IL-10 showed an overall upward trend with the increase of parity.However,the contents of IFN-γand IgG in the second parity were higher than in the third parity.There was no significant difference between the three immune molecules in different parities and different degrees of inbreeding（P>0.05）.2.The number of 146 Wannanhua sow pig was divided into 8 families according to the boars,33 pairs of clear parent-child relationships were identified.3.The average ROH length of the Wannanhua pig sows group was 13.46 MB,and the average inbreeding coefficient F_ROH was 0.19.Genes in high-frequency ROH re-gions are mainly enriched in signaling pathways such as inflammation and immune response,and cytokine regulation.4.The observed heterozygosity of the 14 STR which selected in this work was 0.309-1,the expected heterozygosity was 0.685-0.928,the polymorphic information content was 0.648-0.914 and the average number of alleles was 12,indicating that each locus was polymorphic.The cumulative exclusion rate of parent-child relationship at 14 mi-crosatellite loci reached 99.99%,indicating that the selected 14 microsatellite markers can identify the genetic relationship of Yixian black pig.In conclusion,this study preliminarily explored and detected the distribution law of three immune molecules in different parities of Wannanhua pig,analyzed the ROH dis-tribution and inbreeding degree of Wannanhua pig,and made a preliminary identifica-tion of the genetic relationship of Yixian black pig.The research results have certain reference significance for the healthy breeding and resource utilization of southern An-hui pigs.Secondly,the SNP marker technology and microsatellite marker system used in this work have practical significance for establishing complete,accurating pedigree data,scientifically formulating breeding plan and preventing inbreeding.