Preliminary Study On Detection Of Goat Paratuberculosis And MHC-DRB3 Gene And Paratuberculosis Infection-related Disease Resistance

The production mode in Inner Mongolia is mainly animal husbandry,and para-tuberculosis is widely prevalent in the western part of Inner Mongolia.Most goats with para-tuberculosis will gradually lose weight or even die,which brings great economic losses to the breeding industry.Because the MHC gene in goats has a high degree of polymorphism,and it participates in the immune response of the body.From the genetic point of view,in order to compare the differences between MHCⅡ-DRB3 gene of healthy goats and disinfected goats,this study preliminarily explored the polymorphism of MHC Ⅱ-DRB3 gene and the gene loci that may be associated with para-tuberculosis infection in goats.The goats with suspected Mycobacterium para-tuberculosis infection were examined by necropsy and histopathology,and the full genomic DNA of the bacteria in the feces of the goats with the disease was extracted,and confirmed by PCR amplification and sequencing.A total of 122 sheep feces,blood and serum were collected for detection.Pathogens in blood and feces were detected by PCR,antibodies in serum were detected by ELISA,and the samples were divided into two categories: healthy sheep and infected sheep(those negative for pathogen detection and antibody detection were considered healthy sheep).A total of50 samples were selected from 25 samples that were positive for both pathogen detection and antibody detection,and 25 samples that were negative for both pathogen detection and antibody detection.The whole genomic DNA of blood was extracted and the complete gene sequence of DRB3 site was obtained by PCR amplification.Mega 7.0 software was used to compare the genetic differences of MHC Ⅱ-DRB3 loci between healthy sheep and infected sheep,and the different loci of healthy sheep and infected sheep were preliminarily screened out.The results showed that the sheep was diagnosed with para-tuberculosis after necropsy.In 122 goats,43 feces were positive for pathogens,with a positive rate of 35.25%.24 of 122 blood samples were positive for pathogens,with a positive rate of 19.67%.Fifty-five samples were tested positive for pathogens,with a positive rate of 45.08%.Among122 sera,39 were positive for antibodies(31.97%).Twenty-seven samples were positive for both pathogen detection and antibody detection,with a positive rate of22.13%.A total of 32 nucleic acid polymorphic sites were found at MHC Ⅱ-DRB3 sites,and the mutation rate was 13.22%.Among them,29 polymorphic sites were not related to disease,accounting for 90.62% of all polymorphic sites,and 3 polymorphic sites were possibly related to disease,accounting for 9.38% of all polymorphic sites.