OBJECTIVES: Currently, many questions regarding the effect of anaesthetics to fish remain unresolved. Fish species may differ widely in their response to an anaesthetic, the screening of dosages is often necessary. The aim of this study was to compare the effect of tricaine methane sulphonate (MS 222), clove oil, 2-phenoxyethanol and Propiscin on haematological profiles, oxidative stress biomarkers and antioxidant enzymes in barbel (Barbus barbus). DESIGN: The haematological profiles, oxidative stress biomarkers and antioxidant enzymes of barbel were evaluated immediately after a 10 min anaesthesia (MS 222--100 mg.L(-1), clove oil--33 mg.L(-1), 2-phenoxyethanol--0.4 mg.L(-1), Propiscin--1.0 mg.L(-1)), and 24 h after anaesthesia. RESULTS: The 10 min exposure in the recommended concentrations of tested anaesthetics have no significant effect on haematological profiles, levels of thiobarbituric acid reactive substances, and activity of glutathione reductase of barbel. The activity of superoxide dismutase (SOD) was significantly decreased (p<0.01) in the muscle in all experimental groups. The activity of SOD showed a significant decrease (p<0.01) in the liver 24 h after all anaesthetics; however in the gill the activity of SOD was significantly increased (p<0.01) in Propiscin (10 min). The activity of catalase (CAT) was significantly increased (p<0.05) in the muscle 24 h after all anaesthetics. CONCLUSIONS: The observed effects on barbel antioxidant systems may be a defence against oxidative damage. The results of this study suggest that the antioxidant systems of barbel are altered by Propiscin anaesthesia, but are slightly affected by MS 222, clove oil, and 2-phenoxyethanol anaesthesia.

University of South Bohemia in Ceske Budejovice Faculty of Fisheries and Protection of Waters South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses Research Institute of Fish Culture and Hydrobiology 5 Czech Republic