The efficacy of a poultry commercial anticoccidial vaccine in experimental challenge with Eimeria field isolates

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 forcontrolling coccidiosis in chickens. Considering the immunological variation of Eimeria strains, the efficacy of live coccidiosis vaccines may be compromised. To evaluate the efficacy of a commercial anticoccidial vaccine in poultry, vaccination was followed by experimental challenge with 3 Eimeria field isolates. 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. Vaccinated challenged groups (VC) gained less weight than the un-vaccinated un-challenged (UVUC) birds (p£0.05). Fourteen days post-challenge, theweight 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 theirassociated UVC groups (‌p<0/05‌). Lesion score and FCR were significantly improved in VC groups comparing with their UVC counterparts (‌p<0/05). 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.