Effects of copper (Cu), zinc (Zn), cadmium (Cd) and their mixture some hematological parameters of oreochromis niloticus

Since physiological changes in metabolic parameters are important factors in determining the stress conditions in fish, the aim of the present study was to determine the effects of copper (5 ppm ppm), zinc (5 ppm), cadmium (1 ppm) and their mixtures on hematocrit levels, erythrocyte and nucleus are and on the erythrocyte numbers of O niloticus after exposing the animals over 24, 48 and 96 hours.Hematocrit levels were determined as percentage on a hematocrit scale, erythrocyte counts were made carried by counting under a light microscope and the area of erythrocytes and nucleus were carried on by dyed spreaded slides under microscope.Hematocrit levels showed an increase under the effect o metal mixture after 96 hours of exposure while erythrocyte counts decreased after 48 hours of exposure under the effect of cadmium. No difference was observed in blood parameters at selected concentrations and periods.It can be concluded that the tested concentrations of the metals and exposure periods was too short to observe metal action, the blood parameters returned to normal due to homeostasis within 24 hours or the permanent effect of the metals shows itself in prolonged exposure periods, exceeding 96 hours of exposure in this species.