Performance of Eimeria-challenged male broilers fed 2 ionophore–nicarbazin combinations

Summary: This study assesses the efficacy of 2 different potentiated ionophores (monensin and narasin) and a chemical (nicarbazin, a shuttle) in program with narasin to control coccidiosis in challenged male broilers through the evaluation of performance and macroscopic lesions of internal organs. A total of 4,400 broiler chicks were housed in 44 floor pens of 100 birds each; birds of the first group were fed a narasin/nicarbazin (NN)–containing diet from 0 to 27 D of age followed by narasin diet until market age, and those of group 2 were fed a monensin/nicarbazin diet followed by narasin ration for the same trial periods. The coccidia challenge was performed at day 1 by the inclusion of a proven Eimeria-infected litter in the bedding of all floor pens followed by an oral challenge using a commercial cocci vaccine at 7 D of age with a concentration of 11 times the vaccine dose. Although results showed that NN and monensin/nicarbazin treatments both demonstrated efficacy at reducing coccidian lesions, NN significantly increased BW and reduced feed conversion ratio (P < 0.05) at 27 (1,405 vs. 1284 g and 1.458 vs. 1.566, respectively) and at 33 D of age (2,178 vs. 2,026 g and 1.549 vs. 1.642, respectively). Weight and weight percentages of the ready-to-cook carcass and carcass cutup parts were significantly improved by NN. Narasin/nicarbazin inclusion in diet for 0 to 27 D followed by narasin until market weight was a successful strategy because, in addition to preventing and controlling coccidiosis, it improved performance of broiler chickens.