Effects of Cold Shock on the State of the Antioxidant Enzyme Complex in Tissues of Scorpaena porcus L., 1758

Under experimental conditions, the influence of cold shock on the level of oxidative stress and the state of the antioxidant (AO) enzyme complex in the tissues of the Black Sea scorpionfish (Scorpaena porcus L., 1758) was investigated. The control group of fish was kept at 18 ± 1°C. For the experimental group, the water temperature was lowered to 6 ± 1°C over 30 min. The exposure lasted 3 h. In the gills, white muscles, and liver of fish under cold shock conditions, an increase in the content of thiobarbituric acid reactive substances (TBARS) was observed. The maximum TBARS levels were noted in the fish liver—12–13 µmol malondialdehyde (MDA) mg−1 of tissue. Meanwhile, the response of the antioxidant (AO) enzyme complex in these tissues did not coincide. In the gills and white muscles (peripheral tissues), a decrease in the activity of catalase (CAT) and superoxide dismutase (SOD) was noted. In the liver, conversely, the activity of these enzymes significantly increased by 67–76% (p ≤ 0.01). This indicates that this organ is directly involved in neutralizing reactive oxygen species. In the scorpionfish brain, all investigated parameters remained at the control level. The absence of statistically significant changes in the TBARS content and SOD and CAT activity in the brain generally reflects the resistance of this species to cold shock, which is consistent with its ability to exist in Black Sea upwelling zones.