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

Abstract

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 () 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 (<3 min) with uneventful recovery (<5 min). In light of the secondary and oxidative stress responses of fish transported using TMS®, which were generally not significantly different compared to responses of fish transported in anaesthetic-free water, sedation with 20 mg/L is not advantageous and therefore is dispensable for the transport of this species for up to 10 hr.