Humoral immune response of chickens following vaccination with different Newcastle disease vaccines
In spite of numerous vaccines and different vaccination schedules used in the control of Newcastle disease (ND), prevention and control remain a challenge. This study evaluated three different ND vaccines. A total of one hundred and twenty, day-old brown pullets obtained from a commercial hatchery in Ibadan, Nigeria were used for the experiment. The birds were randomly assigned into 4 groups in which groups A, B and C were vaccinated on days 1, 21 and 42 of age, while group D served as unvaccinated group (control). Hitchner B1 (HB1), Clone-30 and F-Strains were used as the primers for the 3 vaccinated groups respectively. Blood samples were collected from all birds in each group on vaccination day and assayed for NDV antibody by Haemagglutination-inhibition (HI) test. Twenty five chickens from each group were challenged with virulent Newcastle disease virus (Kudu 113 strain) at 3rd week after the last vaccination. The mean antibody titres of the chickens from the vaccinated groups at 3rd week post primary vaccination showed no significant difference. However, a significant difference existed following secondary vaccination with La Sota and Komarov strains at 3rd and 6th weeks of age. A good immune response and clinical resistance were observed in group of chickens vaccinated with Hitchner B1 and Clone-30 as primers than those vaccinated using F-strain. Therefore, Hitchner B1 or Clone-30 is better primer for vaccinating chickens against Newcastle disease.
Keywords: Chickens, Vaccination, antibody, Newcastle disease, Challenge virus