Evaluation of the Antibody Titration in Vaccinated Chickens Against Infectious Bronchitis Virus Using Three Commercial ELISA Kits

Infectious bronchitis is an economically important disease, especially in chickens. It causes disorders in the respiratory tract, kidney and reproductive tract of affected birds. The annual losses imposed by the disease are significant in the Iranian poultry industry. The Infectious bronchitis virus has many different serotypes and mutations in its RNA results in the virus variation which makes the control of IB more difficult. The control strategy of IB is based on vaccination and it has been used live and inactivated vaccines. Vaccines against different strains of the virus have been used. Vaccines should be against specific strains in each area. The application of an appropriate ELISA kit which can detect the level of antibody response leads to choosing an effective vaccine. The current study compared antibody response after four vaccination approach and then compared 3 ELISA kits in the detection of antibody rising. A total of 100 SPF chickens were divided into 5 groups. The first group considered as the control and H120-H120, H120-1/96, H120-4/91, and H120-IB88 protocols were conducted for the 2nd</sup>, 3rd</sup>, 4th,</sup> and 5th</sup> groups respectively. The validation of the Proflok, BioChek and IDEXX ELISA kits were evaluated after vaccination. Significant titers differences between four vaccination approaches were shown better by Biochek, Idexx and Proflok kit respectively. Also, the highest antibody titration belonged to the 4th</sup> group and the highest titration detected by the Proflok kit which had the most sensitivity. According to our results, it is important to use endemic strains of the IBV for vaccination to have better cross-protection. In this study, as the 3 studied kits had different sensitivity and specificity, different antibody rising was detected.