EFFECT OF INFECTIOUS BURSAL DISEASE HATCHERY VACCINES ON H5 AVIAN INFLUENZA VACCINATION IMMUNITY IN COMMERCIAL BROILERS | ||||
| Journal of the Egyptian Veterinary Medical Association | ||||
| Volume 79, Issue 2, June 2019, Page 403-416 PDF (647.78 K) | ||||
| Document Type: Original Research Articles | ||||
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| Abstract | ||||
| The following study was carried out to demonstrate the role of IBD vaccine as immunosuppressant and its effect on immune system of birds. Immunosuppression plays an important role in diminishing the ability of the immune system to respond to vaccines making birds less -immune to HPAI. IBD vaccines vary in their adverse effect on the immune system. In this study, four hundred commercial broiler chicks were divided randomly into four groups; - (ve) control G1, + (ve) control G2, HVT IBD vector vaccinated G3 and immune complex IBD (based on intermediate plus H2512 strain) vaccinated G4. Immune complex and HVT vector IBD vaccines were evaluated in terms of their immunosuppressive effect on the ability of commercial broilers to respond to a vaccination program against HPAI of H5 origin. The vaccination program was based on a H5 Fowl pox vector AI vaccine administered at day old followed by administration of an inactivated Re5 H5N1 avian influenza vaccine at day 10 of age. Vaccine take and humoral immune response was measured by Hemagglutination inhibition (HI) test. Mean titers of study groups showed the immune-complex vaccinated group was significantly lower (P<0.05) mean HI titers at 35 and 42 days of age than mean titres of the HVT vector IBD vaccine and the +ve control groups. Macroscopic and microscopic monitoring parameters used to evaluate any adverse effect on the bursa of Fabricius by the IBD vaccines in this study revealed a significant adverse effect of immunecomplex vaccine in comparison to HVT vector IBD vaccine and the control group that could explain the serological variance. Results indicate that immune complex IBD vaccines may affect the efficacy of AI vaccination programs. | ||||
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