Abstract:
Two hundred and fifty (250) white cockerels were used to compare the differences between the intraocular and oral routes of administration of ND vaccine La Sota in adult chickens. At 20 weeks of age, serum samples were collected from the chickens and used to estimate the antibody levels against Newcastle disease virus using heamagglutination inhibition (HI) test. The birds were randomly divided into two groups, G1 and G2. Birds in G1 were vaccinated with ND vaccine La Sota intraocularly while birds in G2 were vaccinated orally. Serum samples were collected from chickens in the two groups weekly and used to estimate the HI antibody. Result showed higher antibody level in the chickens vaccinated intraocularly when compared with those vaccinated orally. There was significant difference (p < 0.05) between the geometric HI titres of chickens in the two groups on days 7, 14 and 28 PV but it did not differ significantly on day 21 PV. Challenge studies showed 100% protection of chicken in the two groups on day 21 PV. We identified Harderian glands’ possible roles in producing local and humoral immunity in intraocular vaccinations and the destruction of some of the vaccinal viruses by gastric secretions in oral vaccinations as the possible reasons for the production of higher antibodies in intraocular vaccination in adult chickens.
