Evaluation of live oocyst vaccination or salinomycin for control of field-strain Eimeria challenge in broilers on two different feeding programs

Live oocyst vaccination as a method for coccidiosis control in broiler production is currently receiving heightened interest from producers and integrators, who have historically relied heavily on anticoccidial use to control infection. Reasons for this elevated level of interest include increased emergence of drug-resistant field strains of Eimeria, bans in the European Union on the use of continuously fed antimicrobials, and consumer pressure within the United States to remove antimicrobial feed additives from poultry diets. This pen study was designed to compare the live oocyst coccidiosis vaccine Coccivac-B with the ionophore salinomycin (Bio-Cox) for controlling field-strain Eimeria in broilers reared on 2 different dietary rations varying mostly in protein concentration. Broilers were reared to 50 d on a 4-phase feeding program. Both experimental diets evaluated in this study were formulated to simulate the diets of a local commercial integrator by season. The dietary protein profile for diet A was 21.5% (starter), 20% (grower), 16.5% (finisher), and 15.75% (withdrawal), whereas diet B had a profile of 22% (starter), 19.6% (grower), 17.8% (finisher), and 17.5% (withdrawal). On d 14 of grow out, field-strain Eimeria oocysts collected from commercial broiler farms in Texas were spray-applied to the litter in all pens. Significant differences in final BW were not observed with regard to diet or anticoccidial control method. Broilers fed diet B had improved (P < 0.05) mortality-corrected FCR during the starter and finisher phases of rearing. Broilers fed salinomycin had lower (P < 0.05) mortality-corrected FCR for the starter and grower phases, whereas vaccinated broilers had lower (P < 0.05) mortality-corrected FCR during the withdrawal period. Cumulative FCR for the entire grow-out period were similar (P > 0.05) for all groups. These results suggest that feeding an appropriately formulated diet while vaccinating broilers as an alternative to the use of an ionophore can result in at least equivalent performance in the presence of a field-strain Eimeria challenge during grow out.