Development of immunity to coccidiosis in chickens administered anticoccidials in feed

New combinations of techniques were employed for comparing the development of immunity of Eimeria tenella in chickens being medicated with 12 different anticoccidials. Broiler-type birds in batteries received a daily measured dose of E. tenella oocysts for 15 consecutive days while the drug was administered at the manufacturer's recommended level. Two or more tests of each drug gave the following ratings: strong suppression, monensin (121 ppm), salinomycin (80 ppm), lasalocid (75 ppm); moderate suppression, monensin (100 ppm), decoquinate (30 ppm), clopidol (125 ppm), and narasin (80 ppm); slight suppression, arprinocid (70 ppm), nicarbazin (125 ppm), and amprolium (125 ppm + ethopabate (4 ppm); no effect, robenidine (33 ppm), zoalene (125 ppm), and aklomide (250 ppm).