| Objective:The epidemic preventions of infectious bursal disease(Infectious bursal diseases,IBD)and Newcastle disease(Newcastle diseases,ND)are still two major challenges to the domestic poultry farming.The application of IBD and ND vaccine in laying hens has achieved a lot of achievements,but in the production the immune effect of IBD and ND still cannot have the good achievement,which caused the body’s immune organ damage that due to the high toxicity of vaccine.The ND-IBD inactivated vaccine has increased the content of antigen through production process improvement.It can reduce the immune times of animal and effectively avoid the defects of living vaccine.The immune effect of ND-IBD inactivated vaccine in commercial laying hens and the immune response of the body to the vaccine still need to be further studied.Therefore,the immune effect of ND-IBD inactivated vaccine on the 1 and 7 day old laying hens was carried out in this study,and the immune effect of ND-IBD inactivated vaccine and IBD living vaccine of 7 day old laying hens was carried out.Then the mRNA expression of immune factors was detected with real-time fluorescence quantitative PCR.The results provide an important basis for the application of ND-IBD inactivated vaccine in the production of laying hens.Specific contents are as follows:Methods:1.Study on the immune effect of ND-IBD inactivated vaccine on the commercial 1-day-old and 7 day layer chickens.360 1-day-old health layer chickens were randomly divided into A,B and C three treatment groups.Group A was blank control group,inoculated with normal saline.Group B was 1 days old vaccine immunization group,injected subcutaneously with 0.3ml ND-IBD inactivated vaccine.Group C was 7 day old vaccine immune group,injected subcutaneously with 0.3ml ND-IBD inactivated vaccine.The test period was 56d.After immunization,the serum was isolated each 7d.The level of ND antibody was detected by hemagglutination inhibition test and the level of IBD antibody was detected by neutralization test.At the same time,Bursa of Fabricius and spleen in all groups were collected.TRIzol method was used to extract the total RNA in Bursa of Fabricius and spleen,and it was reversed to cDNA.The mRNA expression of CD4+,CD8+,IL-6 and IFN-β were detected by real-time fluorescence quantitative PCR.And the attack protection experiment was carried out in each group each 7d after inoculation with ND-IBD inactivated vaccine with 0.2ml IBDV.The pathological changes in bursa of Fabricius and spleen were observed after 72h,and the protection rate was calculated.2.Immune effect comparation of ND-IBD inactivated vaccine and IBD living vaccine on the commercial layer hens.240 1-day-old health layer chickens were randomly divided into A,B and C three treatment groups.Group A was blank control group,inoculated with normal saline.Group B was immunized with 0.3ml IBD living vaccine on 7 days old.Group C was injected subcutaneously with 0.3mlND-IBD two inactivated vaccine on 7-day-old.The test period was 42 days.After immunization,the serum was isolated each 7day,and the level of IBD antibody was detected by neutralization test.At the same time,Bursa of Fabricius and spleen were collected.TRIzol method was used to extract total RNA and was reversed to cDNA.The mRNA expression of CD4+,CD8+,IL-6 and IFN-β was detected by real-time fluorescence quantitative PCR.And the attack protection experiment was carried out in each group each 7d after inoculation with ND-IBD inactivated vaccine with 0.2ml IBDV.The pathological changes in bursa of Fabricius and spleen were observed after 72h,and the protection rate was calculated.Results:1.Study on the immune effect of ND-IBD inactivated vaccine on the commercial 1-day-old and 7 day layer chickens.The results showed that IBD and ND antibody levels in group C were significantly higher than those in group A and group B(P<0.05)at 28～56 days of age.Before 35-day-old,the protective effect of group C was significantly better than the group A,and the difference was 10%.The results of fluorescence quantitative PCR assay showed that the mRNA expression of CD4+,CD8+,IL-6,IFN-β in group C was significantly higher than that of group A and group B(P<0.05)in bursa of Fabricius and spleen at 28～56 days of age.2.Immune effect comparation of ND-IBD inactivated vaccine and IBD living vaccine on the commercial layer hens.Antibody test results showed that:28～42 day age,IBD antibody level of group C was significantly higher than that of group B and group A(P<0.05).Before 35 days of age,the protective effect of group C was higher than that of group B and group A.The results of fluorescence quantitative PCR showed that:at the age of 21～42 day,the expression of CD4+,CD8+,IL-6,IFN-β beta in the bursa of Fabricius and spleen in group C was significantly higher than that in group B and group A(P<0.05).Conclusion:1.ND-IBD inactivated vaccine could increase the antibody levels of IBD and ND and the mRNA expression of cytokines in immune organs,and enhance the immune function of immune system in 7-day-old commercial layer chicken.2.ND-IBD inactivated vaccine could increase the immune effect and the mRNA expression of cytokines in immune organs compared with IBD living vaccine. |
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