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Heterobranchus bidorsalis (mean total length 31.50 ± 2.32 cm SD; mean weight 241.25 ± 30.39 g SD) were exposed to graded levels solutions of cypermethrin concentrations (0.0005, 0.0075, 0.010, 0.125 and 0.0150 ppm) and a control for 23 days. Plasma collected from the fish was analyzed for enzymes; aspartate transferase (AST), alanine transferase (ALT) and alkaline phosphatase (ALP) and electrolytes (sodium (Na+), potassium (K+) and chloride (Cl-) ions. There was a non-concentration dependent increase in ALT activity above the control value of 7.00 ± 3.83IU/L with a peak at 0.005 ppm (16.50 ± 14 IU/L), which was 135.71% above the control value. AST had variable responses with a rise in activity at 0.005 and 0.010 ppm, which were 8.26 and 5.79% above the control value of 30.25 ± 5.38IU/L. A rise in ALP was only noted at 0.005 ppm (37.75 ± 30.40IU/L), being 115.71% above the control value. A concentrationdependent inhibition was recorded from 0.0075-0.0150 ppm with the greatest inhibition of 88.57% at 0.0150 ppm. Sodium ion level was raised between 0.0075-0.0150 ppm concentrations, with a peak value at 0150 ppm, which was 11.25 units (44.55%) above the control value. A drop of 5.85 units below the control value occurred at 0.005 ppm. All the toxicant solutions caused elevation in potassium ion concentration above the value observed in the control (4.90 ± 1.83 mmol/L). Chloride ion levels was raised at 0.005 and 0.0075 ppm, which were 7.93 and 5.05% respectively above the control value (104.00 ± 10.71 mmol/L). Beyond this, there was a concentration-dependent decline in ionic level with the lowest level of 71.50 ± 13.20 mmol/L at the highest concentration. The study suggests that sublethal cypermethrin levels could cause hormone and electrolyte imbalance in the exposed fish, hence caution should be applied in its application especially near water.
Published Date: 2019-04-04; Received Date: 2019-01-28