Immunologic and haematologic effects of methanolic stem bark extract of Azadihiracta indica on chickens experimentally infected with velogenic newcastle disease virus (Kudu 113) strain

Abstract

The study was aimed at evaluating the weight, haematologic and immunologic effects of crude methanolic stem bark extract of Azadihiracta indica stem bark on vaccinated chickens experimentally challenged with the velogenic Newcastle disease virus. One hundred day old cockerels were randomly divided into four equal groups (I, II, III and IV). Birds in all groups were vaccinated with La Sota strain of Newcastle disease vaccine. The birds were challenged with the velogenic strain of Newcastle disease virus (VNDV) at 42 days of age. Following challenge, groups I, II and III were given oral treatment of methanolic stem bark extract of Azadihiracta indica at 200mg/kg, 400mg/kg and 600mg/kg, respectively until day 56 of age, while group IV was not given the treatment. Thereafter, birds in all the groups were assessed for onset of clinical signs, changes in live body weight, humoral immune responses and haematologic changes. The birds in groups I, II and III showed no sign of Newcastle disease while birds in group IV exhibited mild depression and huddling. The mean body weight of the vaccinated-treated groups were significantly (p<0.05) higher than that of the vaccinated-untreated group on day 56 of age. On days 63 and 70 of age, the mean body weight of group III was significantly higher than groups I and II. The mean haemagglutination inhibition titres of group III was significantly higher (p<0.05) than groups I, II and IV. The mean PCV, Hb and RBC values of the vaccinated-treated group was significantly (p>0.05) higher than the vaccinated-untreated group on day 49 of age. The WBC count of groups I and II were significantly higher (p>0.05) than groups III and IV on days 49 and 56 of age. The mean absolute heterophil counts of vaccinated-treated groups was significantly (p>0.05) higher than the vaccinated-untreated group on days 56 and 63 of age. The mean absolute lymphocyte counts of the vaccinated-treated increased significantly (p>0.05) than that of vaccinated-untreated birds days 49 of age till the end of the experiment.

Keywords: Azadihiracta indica, Stem bark extract, Chickens, Newcastle disease, Immune response, Haematological changes