BACKGROUND: The control of coccidiosis in poultry industry
is dominated by prophylactic chemotherapy; however,
drug resistance is a serious problem. Alternative control methods
such as vaccination have been accepted as a practical method for
controlling coccidiosis in chickens. Considering the immunological
variation of Eimeria strains, the efficacy of live coccidiosis
vaccines may be compromised. OBJECTIVES:To evaluate
the efficacy of a commercial anticoccidial vaccine in poultry,
vaccination was followed by experimental challenge with 3
Eimeria field isolates. METHODS: The efficacy of Livacox® Q
anticoccidial vaccine was evaluated on male broiler chicks,
reared in battery cages. Different factors including weight gain,
FCR, OPG (oocysts per gram of feces) and intestinal lesion
scores were assessed. RESULTS: Vaccinated challenged groups
(VC) gained less weight than the un-vaccinated un-challenged
(UVUC) birds (p£0.05). Fourteen days post-challenge, the
weight gain of VC groups challenged with isolate 2 differed
significantly from its un-vaccinated challenged (UVC)
counterpart; however, there were no significant differences in
weight gain of groups challenged by isolates 1 and 3 with their
respective UVC groups. Lesion score and FCR were
significantly improved in VC groups comparing with their
associated UVC groups (p£0.05). Lesion score and FCR were
significantly improved in VC groups comparing with their UVC
counterparts (p|£|0.05). CONCLUSIONS: The present study
suggests that the use of live anticoccidial vaccine has the
potential for improving live weight gains and FCR; nonetheless,
immunity to local Eimeria species should be evaluated
separately and in trial designs it should be more approximate to
the actual field condition.