Immunogenicity of killed and live infectious bursal disease vaccines alone or in combination in broiler chickens

The objective of this study was to evaluate the serum antibody level against infectious bursal disease virus following administration of killed and live vaccines in broiler chickens. 270 day-old chicks were allocated to six groups: group A was vaccinated with D78 on day 19; group B received killed and live vaccines on days 3 and 19, respectively; group C was given killed and live vaccines on days 9 and 19, groups D and E received killed vaccine on days 3 and 9and group F was kept as control. From each group, three chicks were bled on day 3, and also 15 chicks on days 19, 26, 33 and 42. The collected sera were assessed for IBDV-specific antibody by ELISA test. Moreover, six birds from each group were randomly selected and individually weighed at 42 days of age. After killing, bursa Fabricius and spleen were weighed to calculate their relative weights to live body weight. The experimental groups did not show any significant difference up to 19 days of age. On day 26, groups B and D had a higher antibody titer than group F, but there was no significant difference among other groups. On days 33 and 42, groups A, B and C had the highest titers, and serum titer in group B was significantly more than that in groups A and C. The relative weights of lymphoid organs were not affected by vaccination. higher antibody titers were obtained from live vaccine after killed vaccine administration.