The Distribution Of Mycobacterium Avium Subsp. Avium In Naturally Infected Pekin Ducks Tissues And Its Resulting Secondary Amyloidosis

Mycobacterium avium sbusp.avium(MAA)infects various birds including poultry,pet birds and wild birds,and incur chronic contagious avian tuberculosis.MAA has been isolated from diseased pigs and humans.It can be seen that avian tuberculosis is not only harmful to the breeding industry,but also to human health who with compromised immunity.At present,there is no report on the distribution of MAA in naturally infected Pekin ducks tissues and its resulting secondary amyloidosis.In this study,detecting the distribution of MAA in naturally infected Pekin duck,the immunohistochemistry(IHC)and Ziehl-Neelsen(ZN)staining were used and compared.The results showed that MAA could be observed in cells either IHC or ZN.But localization of MAA with immunohistochemistry is more precision.MAA antigen was distributed in epithelioid macrophages of the liver,lung,spleen and kidney,while they were observed in macrophages of the lamina propria and duodenal glands and degenerative myocytes in the pectoralis muscle.The results showed that the detection rates by IHC were similar with ZN staining in liver,lung,spleen and pectoralis muscle,but the detection rates by IHC much higher than ZN staining in kidney and duodenum.In addition,the liver,lung,spleen,kidney,duodenum and pectoralis muscle of naturally infected Pekin ducks were detected amyloidosis by Congo-red staining and potassium permanganate Congo-red staining.And the relative expression level of IL-1β、IL-6、IL-10、TNF-α and SAA2 were detected by quantitative real-time RT-PCR(qRT-PCR).Experimental results showed that liver,lung,spleen,kidney,duodenum and pectoralis muscle of naturally infected Pekin duck were observed amyloid protein,and the expression level of IL-1β、IL-6、IL-10、TNF-α and SAA2 increased from 4 to 43.In conclusion,this study detected the distribution of MAA in naturally infected Pekin ducks using different staining methods,which could provide fundamental research for future research of the pathogenic mechanism of MAA.And IHC could be applied to diagnose the avian tuberculosis because IHC had much higher detection rate than ZN.In addition,the positive results of Congo-red staining and the increased relative expression level of IL-1β、IL-6、IL-10、TNF-α and SAA2 proved that avian tuberculosis could induce the secondary amyloidosis of naturally infected Pekin duck tissues.