Haematological profiles of the African Clariid catfish (Clarias Gariepinus) exposed to methanolic extract of Raphia Hookeri

Abstract

The effects of sub-lethal concentrations of methanolic extract of Raphia hookeri (MERH) on the haematological indices of Clarias gariepinus were assessed in an exposure/post-exposure experiment for 112 days following a static/renewal protocol. Haematological primary (RBC, Hb, Ht) and secondary indices (MCV, MCHC), leucocytes and erythrocyte sedimentation rate (ESR) were evaluated. Significant increases (p<0.05) were recorded in RBC, Ht and Hb concentrations in exposed fish compared to control (unexposed) fish while low MCV, high MCHC values and a significant (p<0.05) reduction in leucocyte counts were observed during exposure period/post exposure period for all life stages of fish. The blood parameters of fish had insignificant variations by 56 days post-exposure periods indicating adaptational responses of fish to unfavourable environmental condition. In conclusion, the use of Raphia hookeri extracts for fish harvest in artisanal fisheries should be discouraged until its structure and activity on target and non-target organisms are elucidated in field based investigations as mechanisms for maintaining homeostatis may become malapdative on the long-term.

Trop. Vet. Vol. 29 (4) 27-43 (2011)