Evaluation of haematological and behavioural changes in Channa punctatus (Bloch) on short-term exposure to a commercial-grade synthetic pyrethroid pesticide

Abstract

This study aims to assess the acute toxicity of commercial-grade Cypermethrin (10% EC) and evaluate the hematological and behavioral alterations in a freshwater fish Channa punctatus upon short-term exposure to Cypermethrin. A four-day static acute toxicity test was performed to estimate the median lethal concentration (LC50) value of Cypermethrin. During the acute toxicity test, the behavior of the control and cypermethrin exposed fish was critically observed and recorded. After completing the acute toxicity test, the hematological effects of Cypermethrin in C. punctatus were evaluated using two sublethal dosages (0.08 mg/L and 0.12 mg/L). Results of the study revealed that this pesticide induced significant mortality in C. punctatus with a 96-h L50 value of 0.263 mg/L. Cypermethrin exposed fish showed hyperactivity, irritability, erratic swimming, frequent surface visit, etc. Exposure to sublethal concentrations of Cypermethrin for a short period resulted in a significant decline (P<0.05) in total erythrocytes count (TEC), packed cell volume (PCV), mean corpuscular volume (MCV), and hemoglobin (Hb) concentration as compared to control groups. In contrast, pesticide-exposed groups had a significant increase (P<0.05) in mean corpuscular hemoglobin concentration (MCHC) and total leucocyte count (TLC). It is apparent from the results of the study that this commercial formulation is toxic to the studied fish. This study also revealed hematological and behavioral alterations in C. Punctatus which could be used as biomarkers for incipient Cypermethrin intoxication.