Preparation and use of autogenous vaccine from Avibacterium paragallinarum (strain Tan 1-05) in layer chickens.

The study was conducted to prepare and evaluate the use of autogenous vaccine from Avibacterium paragallinarum (strain Tan 1-05) in layer chickens. The results showed that all chickens vaccinated with autogenous vaccine with 10(8)CFU/mL in aluminum phosphate gel developed MAT antibodies (GMT of 2.8 log2 to 5.3 log2) against A. paragallinarum infection. Moreover, the results indicated that all chickens (n=6) selected from vaccinated chickens were protected against A. paragallinarum infection after challenge. No A. paragallinarum was isolated from these chickens. Nevertheless, all unvaccinated chickens did not develop antibodies, and all selected unvaccinated chickens (n=6) showed clinical signs consistent with infectious coryza (IC) where two of them died from the disease after challenge. The findings from the present and previous studies showed that the development of an inactivated IC vaccine from local strains if optimized and adopted may be the best possible way of controlling this economically important poultry disease.