Evaluation of Immune Response and Determination of the Proper Administration Time of Infectious Bursal Disease (IBD) Vaccine

摘要

This study was undertaken to evaluate the immune response and determine the proper administrationtime of Infectious Bursal Disease (IBD) vaccine in layer breed. A total number of 10 young chicks (5 vaccinatedand 5 non-vaccinated) were used for this study. A preset vaccination schedule was used and blood sampleswere collected from these chicks from 1 to 35 day old on 5 days interval. ELISA kit for IBDV was used in thestudy. The declined pattern of Maternal-Derived Antibody (MDA) titers in unvaccinated chicks was comparedwith those given IBD vaccines following one selected vaccination schedule. It was observed that MDApersisted in blood level up to 20 days of preventive level (above 1000 titer). When vaccine administered at theage of day 14 by an intermediate plus vaccine (228 E strains), the vaccine derived antibody was graduallyincreasing due to the low level of MDA. The second booster dose given by live intermediate plus vaccine inday 21 played an important role to increase vaccine induced antibody above the preventive level up to the adultperiod of development and chicks remain secured in IBDV affected area. Since MDA can potentially beneutralized if vaccination done at very earlier age, the findings from this study suggest that the first vaccinationmay be most effective if done at 14th day through drinking water. This would allow the maternal levels todegrade such that the vaccine would induce an effective and protective immune response. A booster dose willthen be required around days 21 of age for carrying the flock through adult period of production.