Decay pattern of maternally derived antibodies and antibody response of infectious bursal diseases live vaccine

Abstract

Introduction: Repeated outbreaks of infectious bursal disease (IBD) despite vaccination necessitated this study. Methods: The right age of IBD vaccination, the immunogenicity and the strain of the vaccine were established. Boven gold pullets (n = 150) were used. They were grouped into 6 groups; unvaccinated and vaccinated chicks according to weeks of blood sampling. Both antibodies titres (unvaccinated and vaccinated) were determined by enzyme- linked immune sorbent assay (ELISA). Results: In broiler chicks, the maternally-derived antibodies (MDA) titre decayed from 1,500 ELISA titre at day old to zero at 35 days , while the antibody rose from a titre of 500 at day old to titre of 2000 at 40 days following vaccination and intercepted at a titre of 700 at 21 days. In pullet chicks, the MDA started with an ELISA titre of 1,500 at day old to zero at 38 days of age, while antibodies rose from a titre of 1,100 at day old to 2,000 at 35 days, and then intercepted at a titre of 800 at 22 days of age, hence the breakthrough titre of the live vaccine for pullet chicks. Significance: MDA for broiler and pullet chicks for the chicks from this hatchery completely decayed at 35 and 38 days, respectively and intercepted at a titre of 700. Thus, the chicks should be vaccinated at 21 and 22 days, respectively. Also, poultry farmer should not use the same vaccination days for chicks of different hatchery. The breakthrough titre of the vaccine was 700. Therefore, it is an intermediate plus. The decay was faster in broilers than pullets, hence vaccination days should be early in broilers than pullets.