Objective: Evaluation of the efficacy of inactivated monovalent and polyvalent vaccines prepared from F. coli serotypes in poultry in Iran.
Design: Randomized completely Design.
Animals: Three hundred sixty Arian broiler chicks.
Procedure: In this study monovalent vaccines 078:K80 and polyvalent vaccine were prepared, using native and virulent E.coli serotypes of078:K80, 0128:K67, 02:Kl, 0l24:K82, 01 19:B14 and appropriate adjuvant ALK (S04)2.12H20 and KOH. Three hundred sixty day old broiler chicks were randomly divided into four treatment and one control groups. Birds in each group were injected with 0.5 ml (1.5 x 0) of one of four prepared vaccines by subcutaneous administration in second week and intramuscular administration in third and fourth weeks of age. Before challenge serum antibody titers were measured by the tube and slide agglutination test. Ten days after the last vaccination chicks were challenged with virulent strain of 078:K80, 02K 1 and 012X:K67 E. coli serotypes.
Statistical analysis: Analysis of variance and Scheffe’s test. Results: More than 95 percent of chickens in control group showed colibacillosis and 70% of them were died after challenge with 078:K80, while in vaccinated groups just 3.7 oo mortality was observed. Live and dead challenged chicks of control group had typical lesions of colibacillosis. No adverse effects were noted on growth rate that were vaccinated with monovalent vaccines. Conclusion: The results of this study revealed that inactivated monovalent and polyvalent vaccines prepared from endemic E. coli serotypes are immunogenic and protective in broiler chicks against virulent E. coli. No cross protection was shown among heterologous serotypes. The vaccines do not have any effects on growth rate or carcasse quality in vaccinated chicks. Thus we suggest using the endemic E. coli vaccine to protect broiler chicks against colibacillosis.