Anaesthesia and transport of juvenile tambaquiColossoma macropomum(Cuvier, 1818) with tricaine methane-sulphonate: Implications on secondary and oxidative stress responses

Summary The aim of this study was to evaluate the anaesthetic efficacy and the effect of sedation with tricaine (TMS®), also known as MS-222, on secondary and oxidative stress parameters in juvenile tambaqui, Colossoma macropomum transported in hyperoxia for 2, 6 and 10 hr. Juveniles were placed in aquaria containing six different concentrations of buffered tricaine (150, 180, 210, 240, 270 and 300 mg/L) and the times for anaesthesia induction and recovery determined. Fish transported in hyperoxic conditions were investigated for glycemia, ionic concentration (K+, Ca++, Na+) and osmolality, haematocrit (Ht) and haemoglobin concentration (Hb), partial pressure of gases (pCO2 and pO2), pH and bicarbonate concentration (HCO3−) in whole blood collected from caudal vasculature. Total antioxidant capacity against peroxyl radicals (ACAP), glutathione-S-transferase (GST) activity and lipid peroxidation levels (TBARS) were investigated in gills, brain and liver. All concentrations of TMS® induced deep anaesthesia in juvenile tambaqui in this study. A concentration of 240 mg/L of TMS® was sufficient to induce rapid anaesthesia (