EVALUATION OF EXPERIMENTAL INACTIVATED INFECTIOUS BURSAL DISEASE VACCINE USING A LOCAL LOCAL VERY VIRULENT PATHOTYPE STRAIN

Abstract

Summary By emergence of very virulent infectious bursal disease viruses (vvIBDVs), all classical measures were called into question. In this study an inactivated IBD vaccine with bursal and embryo origins using a recent local vvIBDV isolate, IR499, was prepared. The virus cultivated in both SPF emberyonated eggs and chicks to evaluate the effects of host system on immunogenicity of the vaccine. The results showed that inoculation of broiler breeder chickens with the inactivated IBD vaccine at 20 weeks of age produced significantly greater levels of antibody in comparison with IBD live vaccine and induced antibody titers with a lower variation than the other. The mean antibody titer raised by bursal origin vaccine was significantly greater than other inactivated vaccine and it persisted throughout this study. Our result show that inactivated vaccine with bursal origin induces high level of antibodies, which is essential for protecting of the birds against the vvIBDV strain. Also it shows that including of very virulent strain in inactivated vaccine provides better protection against field vvIBDV strains.