EN
The studies were carried out on the carp aged two years. The analysis of findings revealed a statistically significant changes in reference to: a) the number of leukocytes and neutrophiles, b) the metabolic activity of neutrophiles determined on the basis of the NBT test, c) phagocytosis of the cells of Staphylococcus aureus 209 P, d) the activity of myeloperoxidase of neutrophiles. In addition, there was found in sick fish marked anatomo-pathological changes. These lesions and haematological and immunological changes were especially distinct in the carp with developed clinical changes.