The morphological changes in the blood of the predatory fish species with eustrongylidosis

The article presents the results of the research concerning the morphological changes in the blood of the predatory fish species (perch, pike and zander) сaused by nematodical parasitic disease – eustrongylidosis. The research has been conducted in 2014–2018. It has been found that in the blood of perch with eustrongylidosis the hemoglobin and the red-blood-cell count decreased by 6.87 and 42.11 respectively, the white-blood-cell count increased by 8.95%; the basophils and pseudobasophils count – by 129.17%; the eosinophils and pseudoeosinophils count – by 131%; the number of band and segmented neutrophils increased by 27.92 and 37.5% respectively; the young neutrophils were not registered; the number of monocytes – by 16.34%; the lymphocyte count reduced by 3.27% in contrast with a fish that were not sick with the disease. The significant morphological changes in the blood of pikes with eustrongylidosis were also observed. Thus, the hemoglobin concentration, the number of red blood cells and lymphocytes decreased by 11.02, 26.32 and 3.16% respectively. The total leukocytes count increased by 22.02%; the basophils and pseudobasophils count – by 114%; the eosinophils and pseudoiesinophils count – by 95.83%; the number of band and segmented neutrophils increased by 1.71 and 46.72% respectively; a reduction of the young neutrophil granulocytes amount to 26% was noted; the number of monocytes of the blood increased by 25.83% in contrast with pikes that were not affected by the eustrongylidosis. A reduction of the red-blood-cell and lymphocytes amount, as well as hemoglobin concentration – to 30.05, 4.4 та 6.3% respectively was observed in hematological screening of the blood of zanders. The amount of leukocytes in the blood of infested fish increased by 10.6%; the basophils and pseudobasophils count – by 69.23%; the eosinophils and pseudoeosinophils count – by 116.67%; the number of band and segmented neutrophils increased by 15.58 and 23.27% respectively; the elevation of the number of young neutrophils to 5.75% was registered; the number of monocytes increased by 17.46% in contrast with zanders that were not infested.