Effects of sub-lethal concentrations of copper and lead
on hematocrit and mean cell volume (MCV) levels and on
erythrocyte numbers, erythrocyte and erythrocyte nucleus
areas were determined after exposing Oreochromis niloticus to 4 ppm Cu and 0.2 ppm Pb over 7, 15 and 30 days.
Micro-hematocrit methods were adopted in determining hematocrit levels and microscopic methods were used
to determine MCV, erythrocyte numbers, erythrocyte and
erythrocyte nucleus areas.
Hematocrit and MCV levels and erythrocyte and nucleus areas increased significantly (P<0.05), whereas the
erythrocyte numbers decreased under the effect of both
metals at the exposure periods tested, except at 30 days of
copper exposure.
There was an increase in MCV levels under the effect
of lead and an increase in erythrocyte and nucleus areas
under the effect of both metals with increasing exposure
periods. Prolonged exposure periods decreased other hematological parameters studied.
Hematological parameters studied were higher in fish
exposed to lead compared to copper during the experiments, except the erythrocyte area.
It was concluded that both copper and lead caused significant changes in hematological parameters of O. niloticus which, in turn, affected the physiological conditions of
fish