Studies on the efficacy of different adjuvants in live stock specific bacterial vaccines for turkeys against Bordetella infection and onset of antibody titers in respect to the age of the turkey poults

For evaluating the influence of the age of the vaccinated birds on the development of antibodies, five groups of turkey poults were inoculated subcutaneously at day 1, 7, 10, 14 and 21 of life with vaccine containing inactivated Bordetella avium and Freund's incomplete adjuvant. No matter which vaccine schedule was used, serum antibodies with the ELISA were first detected at the 28th day of life and increased continuously until the 49th day, when it exhibited either a peak or a plateau. Aluminium hydroxide, Freund's complete and incomplete adjuvant and a mineral oil-arlacel-tween-mixture being permitted adjuvants (appendix II EWG 2377/90) and the adjuvant Gerbu 100 were evaluated for their suitability. Turkeys were vaccinated at the age of three weeks and examined clinically as well as serologically up to the 11th week. Humoral antibodies were detected quantitatively using an ELISA for IgG and a microagglutination test for IgM and qualitatively using immunodiffusion. The damage at the application site was rated by measurement of the swelling of the tissue. In the 10th week, the animals were infected with the agent for challenge. The serological examination for IgG antibodies in the ELISA both treatments with Freund's adjuvants resulted in high titers, which differed significantly from the unvaccinated control after 21 days. IgM could be detected from day 7 onwards in all vaccinated groups and showed the highest titers when aluminium hydroxide was used as adjuvant. In the immunodiffusion assay, precipitating antibodies could be found from the first week after vaccination onwards. There was no correlation between the occurrence of precipitating antibodies and ELISA titers. The measurements of the swelling of the tissue in the beginning showed the largest swellings in the animals injected with Freund's incomplete adjuvant and differed significantly from the unvaccinated control. In the 10th week, the animals were infected with Bordetella avium for challenge. In comparison to the unvaccinated animals, all vaccinated turkeys, no matter which adjuvant was used, showed a distinct and significant reduction of the reisolation rate.