Toxicity of Crude Fruit Endocarp Extract of Calabash (Lagenaria siceraria) on African Catfish (Clarias gariepinus) Juveniles

Abstract

Background: Illicit disposal of scraped out endocarp of bottle gourds as part of processing activity for domestic use into the aquatic environment pose a big threat to the aquatic ecosystem. This study investigated the toxicity effects of crude fruit endocarp extracts of L. siceraria on C. gariepinus juveniles. Methodology: 120 mixed sex of C. gariepinus juveniles of mean weight and length (19.59 ±0.42 g; 14.6 ±0.80 cm) respectively were investigated. The fish were divided into 6 groups of 10 fish in each aquarium containing 5, 20, 35, 50 and 65 mg/L concentration of aqueous extract of L. siceraria and 0.00 mg/L (control) respectively with replicates for Four (4) days for acute toxicity analysis. The animals were sacrificed and blood samples collected for biochemical and isolation of the gills and liver for histopathological studies. Results: Experimental media pH, free carbon (iv) oxide, total alkalinity contents increased while dissolved oxygen decreased significantly (P<0.05) with increase in concentration in the acute bioassay. Temperature did not differ significantly (P>0.05) in all the groups thus, did not affect fish survival. Furthermore, AST, ALT and LDH profiles in blood serum of fish exposed to acute concentrations exhibited a significant increase (P<0.05) with increase in concentration. The exposed gills revealed progressive striking histological alterations viz. thickening and shortening of secondary lamellae, degeneration of connective tissue and complete loss of secondary lamella while the liver showed progressive histo-architectural distortions such as hepatic hypertrophy, cellular degeneration (necrosis), haemorrhage and intracellular infiltration with increase in concentration of the L. siceraria extract. Conclusion: Aqueous extract of L. siceraria had adverse effect on juveniles of C. gariepinus, as evident in the negative modification of the body physiology via biochemical and histological investigations, thus toxic to the aquatic life. Further investigations on other vital organs - kidney, heart, GIT and the reproductive organs are recommended.