الفهرس 
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Abstract
The present work was performed for the isolation and identification of P. multocida from different Egyptian layers and breeders’ infected flocks, preparation of locally inactivated vaccine, determination of its safety, efficacy, and potency. Histopathological examination was performed for organs after challenge. For this purpose, 312 samples were collected from suspected dead birds, identified by culture characters and biochemical tests, 47.7% were positive for P. multocida and 53.2% were negative. While 5 out of 8 isolated flocks were confirmed to be P. multocida serotype A by PCR. Pathogenicity test was performed for detecting the virulence of strains. Inactivated Cholera vaccine was prepared from these samples adjuvanted with Montanide ISA70 with percent 30:70 Antigen and oil respectively. The experimentally prepared FC vaccine was administered in 9 weeks aged SPF chickens at the dose rate of 0.5 ml of 2.92×108 CFU through subcutaneous (SC) route in 5 groups. Booster dose was given with the similar dose and route after 3 weeks of primary vaccination. Sera were collected for determination of antibody titer prevaccination and at 7,14,21,28, and 35 days after vaccination. vaccinated chickens were protected against challenge with P. multocida PA:1 and PA:2 strains, where the protection rates were 70 % and 100 % respectively, while they were 10 % and 0 % in the nonvaccinated controls respectively. The re-isolation of bacteria from challenged dead birds of vaccinated PA1 was 30% and PA2 was 0% while non-vaccinated control PA1 was 90% and PA2 was 100%. So histopathological examination of isolated organs was done for challenged dead birds by H&E.