A toxicity test was carried out on 156 juvenile African catfish after two weeks of acclimatisation. Fresh Picralima nitida seed kernels were crushed, extracted using 30% ethanol and 70% distilled water, and concentrated as a stock solution. The definitive static bioassay comprised a control and four extract concentrations (7.5, 10.0, 12.5 and 15.0 ml/10 L), each in triplicate. Behavioural responses, water quality, mortality, haematological, and histopathological alterations in the liver, kidney, and gills were assessed. The extract contained saponins, flavonoids, alkaloids, terpenoids, tannins, and glucosinolates; total flavonoids were 291.58 +/- 0.00 ppm, while saponins were 94.76 +/- 2.27 mg/g. Mortality was 0.00% in the control and 25.93%, 14.81%, 44.44%, and 48.15% at 7.5, 10.0, 12.5, and 15.0 ml/10 L, respectively. Probit analysis gave a 96-h LC50 of 16.66 ml/10 L and an estimated safe concentration of 1.67 ml/10 L. Exposed fish displayed erratic swimming, air gulping, hyperactivity or reduced activity, mucus secretion, spiralling, and loss of equilibrium. Dissolved oxygen declined markedly in treated tanks, especially at 48-72 h. Haematological indices varied across treatments, with lower PCV, Hb, RBC and WBC values at intermediate concentrations and partial recovery at 15.0 ml/10 L, although the analysed parameters were generally not significant at p > 0.05. Histopathology showed mild to moderate hepatic and renal lesions, whereas gill tissues showed no observable lesions under the scoring system used. The study indicates that P. nitida seed extract has toxicological potential in C. gariepinus and should be applied in aquaculture only after proper dose standardisation and safety evaluation.
Keywords: Picralima nitida; Clarias gariepinus; acute toxicity; LC50; haematology; histopathology; dissolved oxygen; plant extract.
Citation: Idowu et al. (2026). Toxicological Effects of Ethanolic Seed Extract of Picralima nitida on Behavioural, Haematological and Histopathological Responses of Clarias gariepinus Juveniles. J N food sci tech, 7(3):1-8. DOI : https://doi.org/10.47485/2834-7854.1071