Curcuma longa essential oil promotes safe anesthesia involving Gabergica pathway in Amazonian fish

The use of natural agents as anesthetics in fish handling aims to minimize stress during handling procedures, such as biometry, sexing and transportation. This study aims to investigate the behavioral and electrocardiographic characteristics and the pharmacological mechanism of action of Curcuma longa essential oil (CLEO) in Colossoma macropomum. The study was conducted on juvenile Colossoma macropomum (18.13 ± 2.1 g) (n = 153), using CLEO concentrations of 125 μL.L⁻¹, 150 μL.L⁻¹, 175 μL.L⁻¹, 200 μL.L⁻¹, and 250 μL.L⁻¹, analyzing anesthetic induction and recovery behavior (Experiment I), electrocardiogram and respiratory activity (Experiment II) and the pharmacodynamic mechanism (Experiment III). Fish exposed to CLEO concentrations reached a deep anesthesia stage in a concentration-dependent manner. However, the effects obtained during anesthetic induction were reversible, both in behavioral parameters and cardiac activity. The mechanism of action was observed after administration of flumazenil 1 mg/kg i.p., which showed greater resistance to loss of postural reflex and shorter latency for recovery. The mechanism of action indicates involvement of inhibitory GABA neurotransmission. The cardiac effects at the concentrations used were compatible with anesthesia, but no arrhythmias occurred that could compromise the hemodynamics of the fish, demonstrating its safety for short-duration anesthesia induction in Colossoma macropomum.