RESUMO
The harmful effect of iron excess was studied in an experiment using fifteen adult sheep. The animals were divided into three groups of 5 each. The sheep of the group I were kept as controls, those of the group II and III were supplemented with iron in doses of 80 and 40 mg/kg body weight (BW)/24 h respectively. The animals of group II died after a period of 3-7 weeks showing anorexia, loss of weight, diarrhoea, depression and symptoms of circulatory and respiratory failure. From the animals of group III one died after 13 weeks, with symptoms of pulmonary oedema, while the other 4 survived for 22 weeks, together with the animals of the control group. The iron-supplemented animals presented increased values of Serum Iron (SI), Total Iron Binding Capacity (TIBC), percent Transferring Saturation (% SAT), Alanino aminotransferase (ALT), serum Alkalin Phosphatase (SAP), Serum Urea Nitrogen (SUN) Creatinine, Phosphorus and decreased values of serum Copper concentration. These parameters were greater in group II. The iron concentration in the liver, spleen, myocardium and kidneys was also much higher than in the controls. The histological examination revealed degeneration of the liver, spleen, myocardium and kidneys in both groups, while cells overloaded with hemosiderin were seen in the third group only. In conclusion, it was shown that chronic intoxication may occur in sheep overdosed with iron. The toxic dose of iron ranged between 40 and 80 (mg/Kg body weight) per day and was close to 40 mg, when iron was administered in the soluble from FeCl3.6H2O.
