Eimeria acervulina infection in chicks fed cobalt in the presence or absence of excess dietary methionine.

An experiment was conducted with young, male, crossbred chicks to investigate the interaction between dietary cobalt, methionine and experimental Eimeria acervulina infection (duodenal coccidiosis). Coccidiosis and dietary cobalt (250 mg/kg) depressed weight gain and efficiency of feed utilization; cobalt toxicity, however, was exacerbated by the coccidial infection, resulting in a depression in performance greater than could be accounted for by the independent additive effect of each entity. Dietary cobalt increased the cobalt concentration of the liver, kidney and gallbladder (with bile); experimental coccidiosis in the absence of excess dietary methionine resulted in a twofold increase in cobalt deposition in the liver and gallbladder. Excess supplemental methionine partially alleviated the decrease in chick performance and the increase in tissue cobalt content caused by dietary cobalt in both healthy and infected chicks, but with a slightly greater efficacy in the coccidiosis-infected chicks.