Serpil ME YONAR
In this study, effect of formaldehyde (CH2O), which is widely used in the treatment of fish dis-eases and as a disinfectant, on some haematological and antioxidant parameters was investigat-ed. For this purpose, fish were exposed to 40 and 120 ppm of formaldehyde for 30 min during 4 days. After 24 hours the last treatment, blood and tissue (liver, kidney and gill) samples were collected from fish. Haematocrit (Ht) value, red blood cell (RBC) and white blood cell (WBC) counts, haemoglobin (Hb) concentration and erythrocyte indexes; mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentra-tion (MCHC) were investigated in the blood samples. Malondialdehyde (MDA) level, glutathi-one peroxidise (GSH-Px) and glutatyon-S-transferase (GST) activity as well as the reduced glutathione concentration were examined in the tissue samples. All of the haematological pa-rameters decreased in the groups treated formaldehyde compared to that of the control group (p
