Nnanke Agbam OJOGU, Paul Aunde ANNUNE, Gabriel Robert OKAYI
Department of Fisheries and Aquaculture, University of Agriculture Makurdi, NIGERIA
Corresponding author: email@example.com, Tel: +2348076476065
Abstract. A Laboratory study was carried out to assess the toxic effects of aqueous extracts of Piptadeniastrium africanum bark on Clarias gariepinus juveniles using the static bioassay with continuous aeration method. Phytochemical analysis of the P. africanum aqueous bark extract revealed the presence of tannins (1.95 %), saponin (2.95 %), flavonoid (5.63 %), Glycosides (1.05 %), Steroid (2.35 %), Terpens, (2.70 %).0 (control), 25, 50, 75, 100, 125 mg/L concentrations were then applied to Clarias gariepinus juveniles (Mean weight: 18.26± 0.04 g) to determine the acute toxicity. The result obtained revealed the 96 h LC50 values to be 42.21 mg/L with 95 % confidence limit of 30.37–58.67 mg/L. Fish exposed to acute toxicity test exhibited behavioural changes such as discolouration, air gulping, erratic swimming, aggression, excessive mucus secretion, and settling at the bottom motionless just before death. Histological assessment of the gills showed that acute exposure of P. africanum bark led to degeneration of primary and secondary lamellae, lamellae with marginal channel dilation, blanketing of the lamellae, hyperplasia of epithelial cells, epithelial lifting and haemorrhage, oedema, necrosis and malformed secondary lamellae of the African catfish. The liver also showed focal necrosis, bile stagnation, nuclear degeneration, hepatocytes with irregular shaped nucleaus, cytoplasmic vacuolation, vascular congestion, bile pigment disintegration and cytoplasic degeneration Hyperplasia of epithelial cells and fusion of secondary lamellae. The toxic effect of the aqueous extract of the plant on C. gariepinus juveniles was both time and dose dependent.
Keyword: Piptadeniastrium africanum, Clarias gariepinus, toxicity, Histology.