Acute Toxicity of Neem (Azadirachta indica A. Juss) Leaf Extracts to Snake Headed Fish, Channa gachua (Ham.) with Special Reference to their Ethological Responses and Some Haematological Parameters

Abstract

-Objective: In the present study, acute toxicity of neem (Azadirachta indica A. Juss) leaf extracts on the freshwater unwanted fish, Channa gachua (Ham) was investigated. Materials and Methods: During the study period, ethological responses in the exposed fish (240 in number irrespective of sex) were observed. Changes in some haematological parameters like haemoglobin content (Hb), haematocrit (Ht), total erythrocyte count (TEC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and blood glucose (Glu) were also measured in the exposed fish (60 in number irrespective of sex) during the acute toxicity test at different time interval. Results: The 24, 48, 72 and 96 h LC 50 values for C. gachua were 21.80, 19.59, 13.95 and 11.18 g/l respectively. Toxicity factor values of this phytopiscicide to the fish were increased with the progress of exposure time. They showed an alteration in their responses with the increasing concentration of neem leaf extracts and time of exposure. A significant elevation in the level of blood glucose in the exposed fish throughout the exposure period was recorded while Hb showed significant change after 24 h and that of MCHC only at 96 h. Conclusions: The study may help to determine the toxic level of the aqueous extracts of neem leaves to the unwanted fish in aquaculture farm and to understand the mode of its action to fish behaviour and haematology.