Toxic impact of zinc salt (ZnSO₄) on some haematological parameters in a freshwater mud eel Amphipnous cuchia (Hamilton, 1822)

Zinc (Zn), a heavy metal present in aquatic environment, has toxic effect on fishes. Present study was to assess toxicity of Zinc salt (ZnSO4) on total erythrocyte count (TEC), haemoglobin (Hb) content (g/dl) and haematocrit value (PCV%) of blood of freshwater mud eel Amphipnous cuchia.

Live fishes collected from ponds were acclimatized in laboratory. TEC, Hb content and PCV% of blood samples collected after 15, 30, 60 and 90 days, of control fishes and fishes exposed to low (0.5mg/l) and high (1mg/l) concentrations of ZnSO4, were determined by standard methods.

TEC, Hb content and PCV% varied respectively from 2.48 x 10⁶/mm³ to 2.70 x 10⁶/mm³, 12.02 g/dl to 12.30 g/dl and 28.50% to 33.60% in fishes in low and from 2.36 x 10⁶/mm³ to 2.60 x 10⁶/mm³, 11.82 g/dl to 12.20 g/dl and 26.20% to 31.50% in fishes in high concentration of ZnSO4 solution, showing decreasing trend in all three blood parameters vis-a-vis their control values viz. TEC (2.74 x 10⁶/mm³), Hb content (12.60 g/dl) and PCV% (34.50%), decrease being more prominent in fishes exposed to high than those to low concentration. The depletion in these blood parameters may be attributed to the haemotoxic characteristics of Zinc (Zn).