Possible Mortality and Nephrosis on C. Gariepinus Juveniles Due to Exposure to Varied Ethanol Leaf Extracts of S. Occidentalis (L.)

ObjectiveThe detrimental effect of the phytochemicals on fish is problematic, thereby making the fish toxicologist have concerns about assessing dose-effect of plants on fish lives. The current study assessed the toxicity-tolerance of Clarias gariepinus juveniles against ethanol leaf extract of S. occidentalis.MethodsA total of 250 Clarias gariepinus juveniles were stocked for the 2-phase experiment; 99 fish samples were deployed for the range-finding test, while 108 were for the main experiment. They were randomly distributed each time in 12 plastic tanks of 35 L capacity containing 9 fish samples each and filled with 10 L of water. Sub-acute renewal bioassay method was adopted. Three concentrations of 3.00, 5.00, and 7.00 g/ 25 cL of ethanol leaf extract of S. occidentalis were prepared and daily dosed with a 5 mL syringe into the plastic tanks in the triplicate arrangement of each treatment for 23 days. The fish samples were fed twice daily, while the dead fish in each tank was monitored and recorded every 24 hours till the end of the test. The increase in concentrations followed the no-effect observation of the 0.5, 1.0, and 1.5 g/ 25 cL used for the fist-phase range-finding test.ResultsAnalysis of variance assessed the data. The mortality rate in this study significantly (p < 0.05) varied across the main experiment’s treatments and increased with increased concentrations. Treatment A (control) showed no visible lesion, treatment B (3.00 g/ 25 cL) showed vacuolation of the epithelial lining's cytoplasm, treatment C (5.00 g/ 25 cL) showed moderate tubular epithelial necrosis, and treatment D (7.00 g/ 25 cL) showed both glomerular and tubular epithelial necrosis.ConclusionThe degree of damage observed increased with an increase in the concentration of S. occidentalis ethanol leaf extract. The study suggested conscious usage of the test plant for any benefits it might be explored not beyond the range-finding test concentration unless other solvents are used for infusion.