Haematological Parameters and Histopathological Alterations in the Gills of Fish, Catla catla Exposed to Azo Dye Acid Red -97

Haematological and histopathological parameters have been recognized as valuable tools for monitoring fish health. This study was conducted to evaluate the chronic toxicity of Acid Red 97 textile dyes on haematological and histopathological alterations using Catla catla as animal model. Fish were exposed to two Sublethal concentrations (1/100th and 1/50th of LC50 = 85mg/l) 0.85 mg/l and 1.7 mg/l of AR 97 for a period of (10, 20 and 30) days. Haematological parameters were observed that with increase of exposure time, total erythrocyte (RBC), haemoglobin (Hb), and packed cell volume (PCV) values decreased but leucocytes (WBC), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values increased. It is believed that observed depression in packed cell volume and haemoglobin values coupled with decreased and deformed erythrocytes are obvious signs of anemia. Resulted changes in erythrocytes and leukocytes after exposing to AR 97 are due to malfunction in hemopoiesis and decrease in non-specific immune system. Histopathological changes observed in the gills of Catla catla were swelling, aneurysm, fusion of lamellae, oedema in primary lamellae, shortened and severe erosions of secondary lamella and lifting epithelial layer and high mucus secretion. Hence, it was concluded that azo dye AR 97 has potential to cause toxicity in fish.