Essential oil from Lippia alba has anaesthetic activity and is effective in reducing handling and transport stress in tambacu (Piaractus mesopotamicus × Colossoma macropomum)

The goal of this study was to evaluate the efficacy of the essential oil from Lippia alba (EOLA) as anaesthetic and stress reducer through handling and transport in tambacu juveniles (Piaractus mesopotamicus × Colossoma macropomum). Juveniles were exposed to different concentrations of EOLA (0, 10, 20, 50, 75, 100, 200 or 300 μL L− 1) to assess sedation, anaesthetic induction and recovery. The plasmatic parameters (cortisol, glucose, paraoxonase and lactate) showed different responses for EOLA in handling (0, 1 and 4 h) and transport (8 h). Fish were anesthetised with 200 μL L− 1 EOLA and subjected to handling showed higher plasma paraoxonase and lower plasma cortisol. Sensory analysis did not show differences in fillet odour and taste between anesthetised and non-anesthetised fish. Tambacu transported with 10 μL L− 1 EOLA presented lower plasma cortisol and un-ionized ammonia in the transport water. The EOLA was effective for anaesthetising tambacu because it tranquilizes the fish and reduces the effects of stress and we recommend 10 and 200 μL L− 1 EOLA for transport and handling procedures, respectively.