بررسی ایمنی زایی واکسن های کشته و زنده ویروس بورس عفونی به صورت مجزا یا ترکیبی در جوجه های گوشتی

The objective of this study was to compare the serum antibody level against infectious bursal disease virus (IBDV) following administration of killed and live vaccines in broiler chickens. Two hundred and seventy day-old chicks were allocated to six groups (A to F): 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, respectively; groups D and E received killed vaccine on days 3 and 9, respectively; and 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 using ELISA test. Moreover, six chicks from each group were randomly selected and individually weighed at 42 days of age. After euthanasia 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 that of 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 those of groups A and C. The relative weights of lymphoid organs were not affected by vaccination. It is concluded that the best immunogenicity has achieved when chickens were immunized with killed and live IBDV vaccines at first and third weeks of age, respectively.