Protium heptaphyllum essential oil from the fruit as a sedative and anesthetic in Rhamdia quelen: influence in cardiac frequency, biochemical, and oxidative parameters

This study aimed to evaluate the effects of Protium heptaphyllum fruit essential oil (PHEO) on the physiology of silver catfish (Rhamdia quelen) during anesthesia and recovery, through studying echocardiograms, oxidative status, and metabolic parameters. Three experiments were performed: (1) 50 silver catfish juveniles were submitted to anesthesia and recovery tests with 300, 400, 500, 600, and 700 mg L-1 of PHEO. (2) Echocardiogram analysis was performed in anesthetized and non-anesthetized fish. (3) Biochemical parameters were evaluated at 0, 30, 60, and 120 min of recovery after being anesthetized for 3 min with 600 mg L-1 PHEO. Times to sedation and deep anesthesia were reduced with PHEO increasing concentrations. The echocardiogram showed a higher cardiac rate in anesthetized fish. Plasma glucose levels increased in control fish through recovery time, but anesthetized fish showed lower levels than controls at 120 min of recovery. Metabolic parameters such as plasma and hepatic glucose did not show changes considering the recovery time of up to 120 min. Hepatic glycogen, lactate, and triglycerides reduced their levels over recovery times. Fish anesthetized enhanced superoxide dismutase activity and thiobarbituric acid reactive substances levels but decreased reduced glutathione (GSH) levels at 30 min compared to controls. After 60 min, GSH values were significantly higher in anesthetized fish than in controls. These results suggest that PHEO at 600 mg L-1 is an effective anesthetic for the rapid handling of silver catfish, providing stable metabolic parameters and enhanced antioxidant responses during recovery. Echocardiogram analysis confirms the anesthetic effect, supporting PHEO as a viable and efficient option for fish anesthesia in aquaculture. The use of PHEO in aquaculture can enhance fish welfare by reducing stress during handling and transportation, potentially leading to improved growth, health, and survival rates.

This work was partially supported by grant PID2020-117557RB-C22 (funded by MCIN/AEI/https://doi.org/10.13039/501100011033 and by the European Union) to J.M. Mancera and J.A. Martos-Sitcha and by grants from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES PrInt, Brazil), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, Brazil, process 406615/2018–7), and Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS/CAPES, process 19/2551–0000655-1) to B. Baldisserotto. B. Baldisserotto also received a CNPq research fellowship (process 301225/2017–6).

Peer reviewed