Cedrus Atlas (Cedrus atlantica) essential oil induces anesthesia in Amazonian fish: a compartmental, electrophysiological and metabolic study

The study aimed to evaluate the anesthetic and physiological effects of Cedrus atlantica essential oil (CAEO) in Colossoma macropomum (tambaqui), an important Amazonian fish species in South American aquaculture. Fish were exposed to different concentrations of CAEO (10–80 µL·L⁻¹) to determine induction and recovery times. Behavioral and compartmental responses were monitored, along with cardiorespiratory and metabolic parameters, including heart rate, ventilation frequency, and blood glucose. Electrophysiological activity was assessed through electroencephalography (EEG) and electromyography (EMG). Chemical composition of CAEO was analyzed by gas chromatography–mass spectrometry (GC–MS). CAEO promoted rapid and reversible anesthesia, with dose-dependent induction and recovery times. Electrophysiological recordings revealed decreased cortical wave amplitude and frequency, indicating central nervous system depression. Cardiorespiratory and metabolic analyses demonstrated reduced ventilation rate and glycemic stability, suggesting mild systemic stress. Limonene (42.3%) and β-himachalene (35.7%) were identified as major constituents, contributing to the observed anesthetic profile. Cedrus atlantica essential oil acts as an effective natural anesthetic for C. macropomum , reducing neural activity and stress-related responses while ensuring safe recovery. These findings highlight its potential as an eco-friendly and sustainable anesthetic alternative for fish handling and transport in tropical aquaculture.