EN
The aim of the investigations was to trace histopatho- logical and histochemical changes in the selected internal organs of bulls fed Cu-deficient diet supplemented with CuSO,. The experiment was done on 18 Black-and-White bulls aged one year and a half for three months. Half of the animals (group A) were given diet containing 4.7 mg Cu/kg of dry matter while the other half (group B) were kept on the same diet supplemented with Cu up to 10 mg/kg of dry matter. In the group A copper content amounted to 7.10 pmol/L -of serum, 740 gmol/kg of liver dry matter, 143 umol/kg of kidney dry matter and 142 pmol/kg of hair dry matter. In group В these values were higher and amounted to 9.33 gmol/L of serum 2460 pmol/kg of liver dry matter, 203 umol/kg of kidney dry matter and 212 pmol/kg of hair dry matter. In all the bulls of the group A morphological changes were found only in kidneys and in the liver. In the liver swelling of hepatic cells around the central veins of lobules, appearance of cytoplasmic granules and disappearance of glycogen were observed. On the lobule circumference, hepatic cells were more eosinophilic and they contained more glycogen. In kidneys, congestion of the vessels among canaliculi, the presence of numerous foci of the connective tissue proliferation in the medulla section and abnormal thickening of basal membranes of the vessels in the glomeruli were noted. In the group В histochemical examinations showed the higher activity of acid phospatase and the higher activity of both lactic dehydrogenase and succinic dehydrogenase but on the circumference of hepatic lobules only. In the group В this phenomenon was not observed.