Anticoccidial efficacy and chicken toleration of potent new polyether ionophores. 2. The portmicin relative CP-84,657.

The current study investigated the anticoccidial activity of the ionophore CP-84,657 against laboratory strains of the five major pathogenic species of Eimeria that infect poultry. Based on lesion scores and weight gain, the ionophore CP-84,657 achieved broad-spectrum anticoccidial efficacy in battery trials at doses of 4 and 5 ppm that was equivalent to reference commercial ionophores. In uninfected chickens, 4 ppm of CP-84,657 was the highest dose that gave growth rate and feed efficiency equivalent to commercial agents over 21 days in batteries and 49 days in floor pens. Ionophore CP-84,657 is an efficacious, well-tolerated anticoccidial in chickens, with potency comparable to that of the most potent known ionophores.