Diagnosis Of Paratuberculosis In Goats And Its Correlation With MHC And Other Genes

Paratuberculosis is a chronic intestinal infectious disease caused by Mycobacterium avium subsp.paratuberculosis(MAP),which is widespread in several countries around the world,seriously endangering the health of ruminants,causing huge economic losses to livestock industry.Because ruminants infected with paratuberculosis have been in the subclinical period for a long time,irregular disinfection into the environment has caused the scope of infection to expand.Currently,due to the lack of effective vaccines and the high cost of group treatment,there is no effective prevention and treatment method to control the spread of paratuberculosis.Therefore,it is possible to explore candidate genes and SNPs associated with paratuberculosis from the perspective of host genetics for anti-disease breeding.Many studies have shown that MHC gene is closely related to the immune response of the body and the production of certain pathological states.This study searches for SNP associated with paratuberculosis by analyzing the single nucleotide polymorphism of MHC genes in MAP susceptible goats and disease resistant goats.In addition,the excavation of other potential candidate genes provides a theoretical basis for the research of paratuberculosis.Collect intestinal and mesenteric lymph node tissues of goats at a farm in Inner Mongolia,extract DNA,and use primers IS900 and IS1311 for detection and sequencing of Mycobacterium paratuberculosis.Use primers DMC529,531,and 533 for typing and identification of Mycobacterium paratuberculosis;Collected the feces,blood,and serum of 106 goats from the same farm,used nest PCR to detect MAP in feces and blood,and ELISA to detect MAP antibodies in serum;Select 30 goats that tested negative and 30 goats that tested positive for MAP,and use their blood DNA samples for genome resequencing.Through SNP detection and selective sweep analysis,SNP sites of MHC genes related to paratuberculosis were found,and disease related genes were used for GO enrichment and KEGG enrichment,and candidate genes related to paratuberculosis were excavated.The results showed that by PCR detection of the goat’s intestinal and mesenteric lymph nodes,it was confirmed that the goat was suffering from paratuberculosis,and the infected Mycobacterium paratuberculosis was cow-type;Nested PCR was used to detect MAP in the feces and blood of 106 goats,with a positive rate of30.18%.ELISA was used to detect MAP antibodies in the serum of 106 goats,with a positive rate of 15.09%.And a total positive rate of 36.70%;By comparing the MHC gene of MAP susceptible group and resistant group with the reference genome,a total of 72 mutation sites were found,including 43 SNP sites possibly related to paratuberculosis,24 SNPs in MAP susceptible group and 19 SNPs in MAP resistant group,including 17 A/G and 10 C/T conversions,accounting for 62.79% of paratuberculosis related mutation sites.GO and KEGG enrichment analysis was carried out for disease related genes in MAP susceptible group and resistant group respectively.Among them,candidate genes that related to the disease resistance of paratuberculosis are ACP1,MTMR14,PTEN,SSH2,ENPP3,CTNNA2 and TRAF3;Candidate genes that related to susceptibility to paratuberculosis include LOC102172037,LOC102185900,AADAT,ALOX12 B and PLB1.This study provides a new theoretical basis for the prevention and control of paratuberculosis.