Effects of levamisole on the immune response of broilers against Newcastle disease vaccines

The efficacy of levamisole (LMS) hydrochloride, a standard immune modulator, was conducted on 240 broilers using different commercial Newcastle disease (ND) vaccines. La sota, Clon 30 and Avinew vaccines were used in this study. Treated groups received 30 mg/kg of LMS in drinking water for 2 days before and 2 days after each vaccination. Vaccination program were based on routine vaccination in Urmia area. Blood samples were obtained from wing vein on 1st, 14th, 28th and 42nd days. Antibody responses were measured using haemagglutination inhibition (HI) technique. The results of this study show that LMS increased the antibody levels against ND and significant results were seen in Avinew (28th day) and La sota (28th and 42nd days) vaccinated groups. Although, other treated groups showed higher antibody rate compare with control groups; no significant results were documented in those groups. In conclusion, LMS can stimulate immune system which causes better response to vaccination. Further studies are needed to evaluate other effective factors for each of the best results of LMS inclusion in broiler diet.