Feed additive interactions in the chicken: reduction of tissue copper deposition by dietary roxarsone in healthy and in Eimeria acervulina-infected or Eimeria tenella-infected chicks.

Interactions among roxarsone, copper, and coccidiosis were studied in growing crossbred chicks. Corn-soy or corn-soy-corn gluten meal diets were fed in all assays. In the absence of supplemental copper, 50 mg/kg roxarsone did not affect gain. However, in the presence of 250 mg/kg supplemental copper, there was a depression in gain due to feeding 50 mg/kg roxarsone. In contrast, at a toxic level of copper (1000 mg/kg), a growth response resulted from feeding roxarsone. In all instances, roxarsone markedly decreased liver copper concentration in birds fed high levels of copper. Multiple crop intubations of Eimeria acervulina or Eimeria tenella depressed performance and exacerbated copper toxicity symptoms. Copper supplementation as well as coccidial infection resulted in depressed plasma pigmentation.