In Process Quality Control Factors Affecting Potency of Fowl Cholera Vaccine

Fowl cholera (FC) is one of the respiratory syndromes of commercial layer, breeder and broiler farms in Pakistan. The disease is mainly controlled by vaccination. In the present study, effect of “in process quality control” factors such as amount of immunogen, chemical nature of adjuvant, fractions of bacterial culture and its storage on potency of the vaccine was investigated. Immunogen amount (1011CFU/ml) induced serum anti-Pasteurella multocida ELISA (anti-PM-ELISA) antibody titer in the vaccinated birds on 32 days post vaccination that was significantly higher (P<0.05) than that of 109 and 1010CFU/ml. Montanide based whole culture vaccine induced better antibody response as compare to aluminum hydroxide gel. Washed culture of P. multocida (bacterial sediment) induced significantly higher anti-PM-ELISA antibody titer as compared to the vaccine prepared from purified LPS or whole culture vaccine (p<0.05). Storage of oil based FC vaccine at refrigerated temperature for six months did not affect its immunogenicity.

It is concluded that amount of immunogen, chemical nature of adjuvant, freeing of bacterial culture from LPS and media components and maintenance of cold chain are in process quality control factors affecting potency of the vaccine.