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The present work was designed to explore the effect of usage of Ceftiofur sodium (Excenel®) 0.2 mg/bird on the immune response of broilers vaccinated with newly developed Gumboro (IBD) vaccine; Vaxxitek® ( herpes virus of turkey that used as a vector expressing the protective gene of IBDV gene ; HVT+IBD vectored vaccine ).One hundered and fifty day old commercial broiler chicken were divided into 5 equal groups as follows:G0: non IBDV vaccinated, non Excenel® treated and non challenged (negative control).G1: non IBDV vaccinated, non Excenel® treated and challenged with vvIBDV isolate on the 28th day of age (positive control).G2 : non vaccinated but Excenel® medicated with 0.2 mg/ bird s/c at day old and on the 14th day old and challenged.G3: Vaxxitek® vaccinated at day old (0.2 ml s/c injection) and Excenel® medicated with 0.2 mg/ bird s/c at day old and on the 14th day old and challenged.G4: Vaxxitek® vaccinated at day old (0.2 ml s/c injection) but not Excenel® medicated and challenged. Non vaccinated birds treated with Excenel® showed significant decrease in the lymphocyte transformation index compared with the chicken of the negative control, G3 chickens displayed significant suppression on the 3rd, 7th and 14th days of age compared with stimulation index of the G4 chickens. Groups 3 and 4 had significantly higher antibody titres than the other groups. After the challenge with vvIBDV strain, G 3 and G4 were significantly with higher ratios .Bursal/body weight index and the protection level of Vaxxitek® against bursal damage , mortality and morbidity was very high so it can be concluded that, the newly developed technologies against IBDV including (HVT-IBD vectored vaccine); Vaxxitek® gives better outcomes on the immune response in birds medicated on Excenel in addition, it provides a very satisfactory protection levels against IBDV that was early and high enough to a level which protects the chickens from the challenge against IBD virus escaping from the immunity gap between the MDA (maternal derived antibodies )decline and vaccine reaction. |
