Evaluation of killed infectious bronchitis vaccine from different commercial strains

This study was conducted to evaluate multivalent inactivated infectious bronchitis (IB) vaccine from the commercial IB (H120, Ma5 and 491) strains on the Abs response (titre) in chicks reared up to 40 days. Two hundred and fifty broilers (Ross breed) at one day old were divided randomly into 5 groups (50 chicks of each group) diet and drinking water offered ad libitium, experimental groups vaccinated as follows: Group A: Vaccinated with 0.2 ml inactivated IBV vaccine. Group B: Vaccinated with 0.3 ml inactivated IBV vaccine. Group C: Vaccinated with 0.5 ml inactivated IBV vaccine. Group D: Vaccinated with 0.25 ml inactivated ND+IB (Commercial). Group E: Control group. All groups except the control group vaccinated with IBV at 4 days old via subcutaneous route, and vaccinated with attenuated ND+IB (Volvac®) at one day old via ocular route, and vaccinated with attenuated IBD (Ceva®) at 14 days old via drinking water route, and vaccinated with live ND (La sota strain) (Boehringer®) at 10 and 20 days old via drinking water route. All groups were challenged with local virulent IBV isolate (Variant 2 and QX) at 28 days old. Morbidity and mortality were recorded in all the challenged birds. Blood samples were collected from jugular vein at (7, 14, 21, 28, 35 and 42) and transported to the laboratory for serum separation which were used in the ELISA and HI test to determine the antibody titer against IBV. Statistical analysis showed that ELISA and heamagglutination inhibition (HI) antibody titer of IB are antigen specific after challenge with local isolated of IBV (QX and Variant2) strains, group C were significantly (P ≤ 0.05) higher than other groups and control group