Variations in Plasma Biochemical Parameters of Clarias Gariepinus Exposed to Sub-Lethal Concentrations of the Methanolic Extracts of Raphia Hookeri

Abstract

Altered activities of selected biochemical indices in Clarias gariepinus as a response to sub-lethal concentrations of the methanolic extract of Raphia hookeri (MERH) were evaluated in a 112-day exposure/ post-exposure period following static/renewal protocols. Biochemical parameters selected for this study included aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH); total protein, albumin and globulin. Significant increases (p<0.05) in plasma enzyme activities (LDH, ALT, AST and ALP) were recorded in all exposed fish (except in control exposures) while total protein values were significantly lower (hypoproteinaemia) than control (p< 0.05) as a result of marked reduction in albumin levels (hypoalbunaemia) with increasing concentrations of toxicant. The biochemical parameters of fish had insignificant variations by 56 days post-exposure periods indicating the development of a new homeostatic balance by fish to unfavourable environmental conditions. Exposure of C. gariepinus sub-adults to MERH resulted in increased plasma activities of biochemical enzymes and hypoproteineamia (indicative of metabolic crises) and since it is a common practice that plant poisons are tied in bundles by artisanal fishermen and fish are exposed to lethal concentrations of such bundles in open waters; the use of Raphia hookeri extracts for fish harvest may impact negatively on fish physiology. It is thus suggested that such practice should be discouraged in view of evidenced change in fish plasma enzyme activities.

Keywords: Raphia hookeri, Methanolic extract, Sub-lethal concentrations, Biochemical parameters, Clarias gariepinus