Changes in selected haematological and enzymatic parameters of Heteropneustes fossilis exposed to sub-lethal toxicity of rotenone

Abstract

Physiological changes associated with rotenone toxicity in fish was studied by exposing stinging catfish, Heteropneustes fossilis to 1/50, 1/10 and 1/2 sub-lethal concentrations of 48 h LC50, i.e., 0.004, 0.021 and 0.107 mg l-l of rotenone, respectively. The haematological and enzymatic parameters studied in general showed dose-dependant changes in response to the toxicant concentrations. The initial haematological responses in toxicant-exposed fish included reduction in total erythrocyte counts and haemoglobin content, and increase in total leukocyte counts and plasma glucose level. Activities of enzymes such as aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), gamma glutamyl transpeptidase (GGT) and acetylcholinesterase (ACLE) showed varied responses. Changes in haematological parameters, increase in the ASAT, ALAT and GGT and inhibition of AChE concentrations observed in the study suggested prevalence of hypoxic stress and tissue damage in the organism due to rotenone toxicity. The reduction of rotenone toxicity within 24-48 h post-application suggests low residual problems since most of these parameters returned back to normalcy in the experimental animals.