FISH BLOOD PARAMETERS AS A POTENTIAL TOOL FOR IDENTIFICATION OF STRESS CAUSED BY ENVIRONMENTAL-FACTORS AND CHEMICAL INTOXICATION

Classical stress indicators (cortisol, glycemia, hemoglobin and hemato crit) and specific red blood cell responses of enzymes involved in pro tection against active oxygen species (superoxide dismutase (SOD), cat alase and peroxidase activities) were investigated in sea bass (Dicent rarchus labrax) exposed to decreased salinity, increased temperature ( physical stress) or to intoxication by metallic or organic compounds ( chemical stress). Thermal stress led to a greater increase in glycemia , cortisol and peroxidase activity than osmotic shock, whereas SOD and catalase activities were more stimulated by osmotic shock. The most f requent responses of blood parameters to specific chemical intoxicatio n involved peroxidase and MnSOD activities, and cortisolemia. Increase d levels of cortisol were always found and were followed or not by enh anced glycemia. Pooling these results according to specific chemical f amilies (metallic and organic compounds) revealed a low but general in crease of total SOD activity in intoxicated fish. Some reference value s were also given for each parameter, including possible variations re lated to sex, season or nutritional influences. The effect of fish cat ching, especially on glycemia and cortisolemia, was also evaluated.