Excess Manganese Ingestion in the Chick

Abstract Two experiments were conducted with young chicks to investigate effects of excess manganese, (Mn) ingestion and to compare MnCl2 4H2O, MnSO4 H2O, MnO2, and MnCO3 as sources of dietary Mn activity. Each source of Mn was added to a conventional corn-soybean meal diet to supply 3000, 4000, or 5000 mg/kg Mn. High levels of dietary Mn from MnSO4 H2O and MnCl2 4H2O depressed growth slightly; MnO2 and MnCO3 did not affect chick performance. Manganese dioxide contained less Mn activity than MnCO3, MnSO4 H2O, or MnCl2 4H2O as assessed by relative depressions in hemoglobin and hematocrit and by relative increases in bile, liver, and bone Mn concentrations. Neutralization of the chloride ion in MnCl2 4H2O with NaHCO3 did not ameliorate the adverse effects of excess, MnCl2 4H2O ingestion. Bone and bile Mn concentrations reflected Mn intake better than liver Mn concentration or rate and efficiency of weight gain.