Immunomodulatory Effects of Neem (Azadirachta indica) Leaf Aqueous Extracts in Cockerels Vaccinated and Experimentally Infected with Infectious Bursal Disease Virus

The aim of the present work was to study the immunomodulatory potentials of aqueous extract of Neem (Azadirachta indica) leaf in cockerels vaccinated and/ or infected with infectious bursal disease virus (IBDV). Four hundred and eighty (480) day old cockerels were used and allocated into 8 groups. The birds were grouped as vaccinated/ unvaccinated, challenged/ unchallenged, neem leaf treated/ untreated groups. The IBD vaccines (intermediate plus strain) were given at 14 and 28 days of age while the experimental infection using very virulent IBD virus (vvIBDV) was inoculated at 35 days of age and the extracts were given from day old to 6 week old.Serum samples were collected on first day and on weekly intervals while post challenge, onset of the disease, clinical signs and mortality rate were recorded. The results obtained showed higher antibody titre, faster seroconversion, mild clinical sign and very low mortality in the neem leaf treated groups. These results indicated that the neem leaf aqueous extract has immunomodulatory potentials by increasing the antibody titre post vaccination and the ability to prevent mortality