In ovo-vaccination of chicken embryos with infectious bronchitis virus vaccine

This study was carried out to evaluate in-ovo vaccination against infectious bronchitis virus. Two hundred forty specific pathogen-free fertile Babcock chicken eggs were selected and divided into groups A, B, C, and D (i.e. 60 eggs were kept in each group). The embryonated eggs of group A, B and C were vaccinated with IBV M-41 strain using the manual micro-injection system at 18 days of incubation period while group D were kept as control. After hatching, hatchability percentage, antibody titre in sera of vaccinated chicks was recorded. In-ovo vaccination with different dilution affected the hatchability. The chicks of group A received vaccine at the dose of 0.1 mL with virus serial dilution 10*-6 and showed 83.33% hatchability, group B received vaccine at the dose of 0.1 mL with virus serial dilution 10*-5 and yielded 68.33% hatchability. The chicks of group C were vaccinated with the dose of 0.1 mL (dilution 10*-4), they showed 63.33% hatchability. The chicks of group D receiving no vaccine showed 96.66% hatchability. The blood of all the vaccinated birds was examined for haemagglutination inhibition test at weekly intervals. Clear variation in the antibodies titre was evident. The chicks receiving 0.1 mL (dilution 10*-6) of vaccine had the maximum antibody titre (5.75), followed by the dilution 10*-5 (5.5 titre) and 10*-4 (4.75 titre) at the the end of the 5th week. The antibody titre of the groups A, B and C decreased gradually to 5.00, 4.62 and 3.15, respectively, up to the end of the 7th week. No antibody titre was observed in D chicks.