Dosage regimen associated immuno modulatory effect of levamisole on humoral response of broilers against inactivated avian influenza virus H7N3 adjuvanted vaccines

Inactivated oil based avian influenza vaccines are being used to confront viral outbreaks but seem to be ineffective due to the shorter life span of broiler birds. In such situations immunostimulating agents may play a vital role to overcome the problem. The current study was designed to investigate the co-stimulatory effect of levamisole on humoral response of chicken against inactivated oil based influenza vaccines in broiler birds. The efficacy of levamisole (LMS) hydrochloride, a standard immune modulator was evaluated on one hundred broilers in association with inactivated adjuvanted avian influenza vaccines. Avian influenza susceptible broilers were divided into nine groups, each having ten birds. The birds in groups G1, G2, G3, G5, G6 and G7 were offered 30 , 20 and 15mg kg-1 bwt levamisole for four consecutive days after being vaccinated with oil and gel based inactivated influenza vaccines respectively; birds in group G9 were kept as control. Whereas, birds in Group G4 were kept as oil base vaccinated control and Group G8 were kept as gel base vaccinated control without levamisole medication. Blood samples were obtained from wing vein on 14th, 28th and 36th days post vaccination. Anti-influenza antibody response was measured using haemagglutination inhibition (HI) technique. Data analyzed by one way ANOVA and DMR test showed that levamisole in both regimens had appreciable effect on antibody titers (p<0.05). 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.