Performance of Healthy and Eimeria acervulina-lnfected Chicks as Influenced by Anticoccidial Drugs and Source of Dietary Protein

Four experiments were conducted to evaluate an alleged interaction between the anticoccidial drugs, monensin and lasalocid, and dietary protein source. Chicks were fed practical diets (approximately 24% crude protein) containing from 0 to 13% animal-source protein supplied by either a fish meal-meat and bone meal combination or by feather meal. Monensin (121 mg/kg) and lasalocid (125 mg/kg) were evaluated for anorexigenic activity in health birds and for growth-enhancement activity in E. acervulina-infected birds. Diet-by-coccidiostat interactions were not detected in any of these experiments. The addition of monensin or lasalocid depressed performance significantly in only one of the experiments, but the magnitude of depression was similar regardless of level of animal-source protein. Efficacy of the coccidiostats, as judged by performance of chicks infected with E. acervulina, was not altered by diet type.