Excess dietary copper triggers enlargement of the proventriculus in broilers

Suspect feed was collected from two broiler houses in which random necropsies revealed proventricular enlargement (proventriculitis). Feed also was collected from two unaffected houses and the same farm. Broiler chicks recieved the suspect feed, feed from unaffected houses, and a control feed for 2 wk. Thereafter, all groups were fed control feed until 4 wk of age. The suspect feed caused a 70 to 100% incidence of obvious proventicular enlargement, which was significantly higher than the basal 10 to 30% incidence observed in broilers fed control feed or feed from unaffected houses. The incidence of preventricular enlargement reverted to control levels when birds previously fed suspect feed were switched to control feed during the last 2 wk of the experiment. The suspect feed contained Cu, added as copper sulfate, in excess of 200 ppm. In a second experiment, feeds formulated to contain 0, 250, 500, and 750 ppm Cu were fed to broilers for 4 wk. Dietary Cu at and above 250 ppm significantly increased the incidence of proventriculitis. Dietary Cu in excess of 200 ppm can trigger the classic symptoms of proventicular enlargement and proventriculitis in broilers.