Acute toxicity and adverse effects of aqueous and ethanol extracts of <i>Parkia biglobosa</i> pods on biochemical parameters of <i>Clarias gariepinus</i>

Abstract

The acute toxicity of the aqueous and ethanol extracts of Parkia biglobosa pods against Clarias gariepinus was investigated under laboratory conditions. Agitated behaviours and respiratory distress were also observed during the exposure period. The adverse effects on biochemical parameters were assessed using semi-static bioassays for 28 days. The ethanol extract of P. biglobosa pods was found to be more acutely toxic with a 96 h LC₅₀ value of 13.96 mg l ⁻¹ than the aqueous extracts, with a 96 h LC₅₀ value of 19.95 mg l⁻¹ against C. gariepinus. Both extracts induced agitated behaviours and respiratory distress in exposed organisms. The activities of superoxide dismutase (SOd), catalase (CAT) and the concentration of malondialdehyde (MdA) were significantly lower (p < 0.05) in groups of organisms exposed to extracts of P. biglobosa when compared with the control group after 14 days. The activities of aspartate aminotransferase (AST), alanine  aminotransferase (ALT) and alkaline phosphatase (ALP) were also  significantly (p < 0.05) lower compared with activities of the enzymes in the control group after 28 days. The current study has shown that the introduction of P. biglobosa pods into aquatic ecosystems is acutely toxic to fish and would possibly be to other non-target aquatic organisms especially invertebrates.

Keywords: biomarkers, liver function enzymes, oxidative stress enzymes, piscicidal plants