Necrotic enteritis (NE) caused by Clostridium perfringens type A and colibacillosis caused by Avian pathogenic E. coli (APEC), are two pathogenic diseases that threaten the poultry industry worldwide. A combined inactivated vaccine from Clostridium perfringens type A toxoid and serotypes O1 and O78 of E-coli adjvunated with montanide gel was prepared and evaluated in two weeks old SPF white Lohman layer chickens and its progeny. The prepared vaccine was found safe
and produced antitoxic titre against NE of 10 IU after 22 week of vaccination as measured by serum neutralization test and 2692 ELISA titre. Also it produced a humeral antibody titre against E.coli serotypes used of 80 at the 22th
week post vaccination by microagglutination test (MAT) and an 80% protection in challenge against virulent E.coli serotypes used.
Conclusion: vaccination of chicken with two doses, 3 weeks apart, of combined vaccine of Clostridium perfringens type A toxoid and serotypes O
1 and O
78 of E-coli adjvunated with
montanide gel, could protect against necrotic enteritis and colibacillosis.