Toxicity of aquaeous leaf extracts of <i>Gongronema latifolium</i> on behaviourial and haematological characteristics of <i>Clarias gariepinus</i> (Burchell, 1822) juveniles

Abstract

A static bioassay experiment was set up to investigate effects of acute (96-hrLC50) concentrations of aqueous leaf extracts of Gongronema latifolium on behaviourial and haematological characteristics of Clarias gariepinus (Burchell, 1822) juveniles. Evaluation of toxicity of leaf extracts at concentrations of: 0, 10, 25, 50, 75, and 100mg/l was done at various time intervals on the fish. A total of 180 catfish juveniles with average initial weight of 8.37±1.36g and total length of 12.10±2.45cm were used. The fish were distributed among the treatments on complete randomized design. Each treatment had three replicates. The results showed that aqueous leaf extracts were toxic to experimental fish. There was an observed erratic movement, colour change from black to ash-brown and dark coloured belly of treated fish. There were slight changes in water quality parameters, with no significant effect (p>0.05) on the tolerance level of fish on G. latifolium leaf extracts. Mean values of 96-hrLC50 were 90.14mg/l and 2.78mg/l for the upper and lower limits while the threshold value was 0.26mg/l. Phyto-chemical analysis of the leaves showed constituents of flavonoids, saponins, tannins, anthrocyanide, alkaloids and glycosides. Effects of aqueous extracts on haematological indices revealed increasing values of pack cell volume, haemoglobin, white blood cell, red blood cell, mean corpuscular volume, mean corpuscular heamoglobin and mean corpuscular heamoglobin concentration counts with extract concentration. Thus, G. latifolium could be used as feed additive for improved fish production at concentration below 70%.

Keywords: Gongronema latifolium, leaf extracts, behaviour, haematology, Clarias gariepinus