Electrolytes in Selected Tissues of Heterobranchus bidorsalis Treated With Sub lethal Levels of Cypermethrin

Heterobranchus bidorsalis (mean length 31.50±2.32cm SD; mean weight 241.25± 30.39g SD) was exposed to cypermethrin (0.0005, 0.0075, 0.010, 0.125 and 0.0150ppm) for 23 days to determine the effect of exposure oncations (sodium, Na+, potassium, K+) and anion, Cl- in the gill, kidney, liver and muscle tissue. Hyponatraemia (p>0.05) occurred in the gill except at 0.0075ppm with hypernatraemia (107.33% above control value,105.63±7.48mmol/l). Hypokaelamia was recorded at 0.005 and 0.0150ppm, but concentration dependent hyperkalaemia at 0.0075 through 0.0125ppm. Gill of exposed fish had hypochlorinaemia except at 0.010ppm. Generally, kidneys of exposed fish had hyponatraemia and hypokaelamia relative to the respective control values. There was no change in Cl- level at 0.0125 and 0.0150ppm, but hypochlorinaemia at 0.005ppm and hyperchlorinaemia at 0.0075 and 0.010ppm with 10.78 and 67.09% respectively, above the control value (19.75±4.50mmol/l). In the liver, Na+ levels were lower at 0.0025, 132.50±55.00mmol/l and 0.0125ppm, 206.25±96.20mmol/l, whereas at 0.005, 0.010 and 0.015ppm it was 2.96 (96.36%), 1.49 (48.45%) and 1.70times (70.00%) the control value, 275.00±27.66mmol/l. Hypokaelamia was recorded at 0.005 and 0.0075ppm, whereas hyperkaelamia was noted at the other exposure concentrations with a peak at 0.0150ppm, 23.61% the control value, 18.00±2.94mmol/l. Non-concentration dependent hyperchlorinaemia with about two units above control recorded at 0.0075 -0.0125ppm and about six units at 0.005 and 0.0150ppm (Table 3). In the muscle, sodium, potassium and chloride ions were all elevated (Na+, 72.66; K+, 4.14; Cl+, 54.22%) above their respective control values at 0.005ppm. Generally hyponataemia, hypokaelamia and hypochlorinaemia were recorded in the other exposure levels. The study indicates that pollutants interfere with electrolyte in the organism thereby disrupting the internal physiology of the exposed fish. Key words: Cypermethrin, electrolytes, Heterobranchus bidorsalis, tissue