Effects of Neem (Azadirachta indica) Leaf Aqueous Extracts on Haematological Parameters of Cockerels Experimentally Infected with Infectious Bursal Disease Virus

The study aimed to identify the effects of aqueous extract of Neem ( Azadirachta indica ) leaf on some haematological parameters of cockerels vaccinated and infected with infectious bursal disease virus (IBDV). Four hundred and eighty (480) day old cockerels were purchased for the study and allocated to 8 groups. The birds were grouped as vaccinated/ unvaccinated, challenged/ unchallenged and 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 weeks old. Blood samples were collected at 1-week post each IBD vaccination, and vvIBD virus challenge for haematology and the results were analysed and recorded. The results obtained showed heterophilia and lymphopenia in the vaccinated groups while very virulent IBDV strain results in panleucopenia, lymphopenia and heterophilia. However, increased lymphocytes and total white blood cell counts (TWBC) was observed following Neem leaf aqueous extracts administration with resultant decrease in heterophils. These results indicates that neem leaf aqueous extracts enhanced the immune status of the birds by increasing the TWBC and lymphocyte counts.