The evaluation of some infectious bursal disease vaccines on the humoral immune response of chickens vaccinated with Newcastle disease vaccine in Nigeria.

摘要

The effect of four commonly employed infectious bursal disease (IBD) vaccines on the immune response of chickens vaccinated with Newcastle disease (ND) vaccine were assessed in pullets using a pre-existing vaccination regimen, depicting field situations. The antibodies to IBD was evaluated by the qualitative and quantitative agar gel immunodiffusion method while the haemagglution inhibition (HI) test was used for the detection of ND antibodies. The immunosuppressive effect was assessed by: the suppression of the ND titres; the bursa of Fabricius (BF) index; the BF diameter; and the BF histopathological lesions. The results showed that the IBD vaccines caused a transient immunosuppression in the ND vaccinated chicks. This immunosuppressive effect was non existent when a booster dose of Newcastle disease - Komarov vaccine (NDV-K) was administered. Both the BF index and diameter were significantly higher (P<0.05) in the vaccinated groups when compared with the control unvaccinated. Histological lesions in the BF were more pronounced in birds that received vaccine III. There were no significant differences between the BF index and histological lesions as well as the BF diameter and histological lesions in vaccines I, II and IV. This study revealed that the IBD vaccines employed in this study were: immunogenic; did not induce IBD death in vaccinated birds; and were not immunosuppressive when combined with ND vaccination, as they did not depress ND antibody titres.