Effects of various adjuvants on efficacy of experimental inactivated oil Ornithobacterium rhinotracheale vaccine in SPF chickens

The purpose of this study was the effect of vaccination with different adjuvant of inactivated ORT vaccines (potassium alum, mineral oil and Saponin) to measure the levels of antibodies against ORT in blood sera on SPF chickens. Inactivated ORT bacterin vaccines were prepared from ORT serotype A using potassium alum, mineral oil (MO) and Saponin. Fifteen SPF chickens per group were vaccinated at an age of 3 weeks with one of the three different inactivated vaccines. Similarly, 15 SPF chickens at an age of three week were vaccinated with inactivated vaccine in mineral oil. Booster vaccination with inactivated vaccine in mineral oil was performed five weeks after primary vaccination. Blood samples were collected from all the experimental birds during the experimental study. The presence of IgG antibodies against ORT antigens in SPF chickens were measured by using a modified ELISA, which were prepared in our laboratory. In this study, the levels of antibodies to ORT in blood sera of vaccinated chickens were significantly determined higher by ELISA than non-vaccinated chickens. These results show that the levels of antibodies of ORT vaccine with Montanide adjuvant were significantly greater than that of other vaccines when humoral responses of all vaccine were compared. According to the results, twice vaccination interval of 5 weeks could be effective for long lasting term than a single administration. In conclusion, vaccination of SPF chickens at 3 weeks of age with a booster dose at 8 weeks of age can be an effective method against ORT in chickens.