This experiment was conducted to study the immunological mechanism of oral vitamin E(VE)a-gainst nephropathogenic infectious bronchitis virus(IBV)infection in specific pathogen free(SPF)chickens.Forty 1-day-old SPF white leghorn chickens were randomly divided into 2 groups with 20 birds per group.Dur-ing 1 to 21 days of age,chickens in the experimental group were orally administered 100 IU/kg VE(dissolved in 10 µL soybean oil),and chickens in the control group were orally administered equivalent soybean oil with-out vitamin VE.Stop oral administration at 21 days of age,all the chicken were inoculated with 0.1 mL/bird nephropathogenic virulent IBV strain via combined intraocular and intranasal routes.The experiment lasted for 24 days.The results showed as follows:1)oral VE had no significant effect on growth performance of SPF chickens(P＞0.05).2)After inoculated IBV,the SPF chickens in 2 groups demonstrated typical clinical symptoms,on 2 dpi(days post infection),the viral load in spleen and bursa of Fabricius of the experimental group was significantly lower than that of the control group(P＜0.05).3)Compared with the control group,the mRNA relative expression level of myeloid differentiation factor 88(MyD88)in lungs,spleen and cecal tonsil(2 dpi)of the experimental group was significantly decreased(P＜0.05),the mRNA relative expression level of MyD88 in lungs and spleen(5 dpi)was significantly increased(P＜0.05),and the mRNA relative ex-pression level of P65 protein(P65)in cecal tonsil(5 dpi)was significantly decreased(P＜0.05).4)Oral VE showed multiple regulation on mRNA relative expression levels of avian beta-defensins genes in tissues of SPF chicken infected with IBV,and little regularity was found.5)Compared with the control group,the mRNA relative expression level of CD8 positive cells(CD8+)in spleen(2 dpi)and cecal tonsil(5 dpi)of the exper-imental group was significantly decreased(P＜0.05).In summary,oral VE has no significant effect on the growth performance of SPF chickens.In contrast,oral VE can inhibit the IBV replication in some tissue,regu-late the gene expression of immune-related factor in tissues,and plays a positive role in the infection effect of chickens against IBV.[Chinese Journal of Animal Nutrition,2024,36(11):7467-7480]
维普
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