Lead toxicity in the chick as affected by excess copper and zinc and by Eimeria acervulina infection.

Several experiments were performed with young chicks to evaluate lead (Pb) toxicity and its effect upon copper (Cu) and zinc (Zn) toxicosis in the presence or absence of Eimeria acervulina infection. Toxic levels of Pb (3300 mg/kg) and Cu (500 mg/kg) or Zn (2000 and 4000 mg/kg) were added to completely adequate corn-soybean meal diets, while duodenal coccidiosis was produced by multiple crop inoculations of 4 X 10(5) sporulated E. acervulina oocysts. Both Pb and Cu depressed gain and feed efficiency while concomitant coccidial infection reduced these parameters further. Moreover, E. acervulina increased the concentration of liver Cu and kidney Pb. Although Pb supplementation slightly decreased the accumulation of liver Cu, additional Cu tended to increase the deposition of Pb in the kidney in both infected and uninfected birds. Similarly, chick performance was significantly reduced by excess dietary Pb or Zn, although coccidiosis slightly ameliorated the growth depression caused by toxic levels (4000 mg/kg) of Zn. Although 4000 ppm Zn and coccidial infection reduced the deposition of Pb in the kidney, this interaction was not evident when 2000 mg/kg Zn was fed to infected chicks. It is evident that Pb toxicosis in the chick is affected little by excess dietary levels of either Cu or Zn.