Eugenol and Lippia alba essential oils as effective anesthetics for the Amazonian freshwater stingray Potamotrygon wallacei (Chondrichthyes, Potamotrygonidae)

Abstract

This study assessed the potential of eugenol and the essential oil of Lippia alba (EOLA) in providing suitable anesthetic induction and recovery times, and their consequent effects on the blood and respiratory physiology, as well as the gill architecture of an Amazonian freshwater stingray, Potamotrygon wallacei, at the onset of the anesthetic event and after 48 h of recovery. Juveniles of P.wallacei (n = 12) were exposed to increasing concentrations of eugenol (75, 100, 125 and 150 µL L − 1 ) and EOLA (150, 175, 200 and 225 µL L − 1 ) in an immersion bath. Anesthetic induction was found to be faster with the use of eugenol compared to EOLA. On the other hand, the stingrays anesthetized with eugenol displayed a longer recovery time than those exposed to EOLA. The highest concentrations of eugenol caused moderate to severe histological changes in the gills. No signi cant changes were found for hematocrit and plasma metabolites in the stingrays anesthetized with all concentrations of both eugenol and EOLA just after the onset of anesthetic action, when compared to those recovered after 48 hours. Investigations regarding the potential use of these natural anesthetics are unprecedented for freshwater stingray species and 200 µL L − 1 EOLA is recommended as the most suitable anesthetic for use in juveniles of P. wallacei.

Essential oil of Magnolia denudata is an effective anesthetic for spotted seabass (Lateolabrax maculatus): a test of its effect on blood biochemistry, physiology, and gill morphology

“…In some studies, extensive histopathological abnormalities were observed in the gill, including hyperplasia, epithelial lifting, and curling of lamellae after exposure to anesthetics (essential oils of A. triphylla, L. sidoides, and M. piperita, MS-222, eugenol), indicating that the gill is a sensitive organ for responding to anesthetics (Brandão et al, 2021;Wang et al, 2020;Lima et al, 2021). In the present study, changes in gill morphology were identi ed using H&E staining and were classi ed in three degrees, according to de Lima et al (2021).…”

Efficacy of fennel (Foeniculum vulgare) and anise (Pimpinella anisum) essential oils as anaesthesics in common carp (Cyprinus carpio L. 1758)

“…Similarly, Yigit and Kocaayan ( 2023 ) reported that thyme essential oil caused marked hyperemia, oedema, inflammatory cell infiltrations and desquamation in gills. de Lima et al ( 2021 ) also reported that eugenol caused moderate to severe histological changes in the gills of the Amazonian freshwater stingray, Potamotrygon wallacei . Brandão et al ( 2021 ) reported hypertrophy and hyperplasia of the lamellar epithelium, lamellar fusion and proliferation of chloride cells in Colossoma macropomum anaesthetized with essential oils of Aloysia triphylla , Lippia sidoides and Mentha piperita .…”

The pharmacokinetic and residue depletion study of eugenol in carp (Cyprinus carpio)

“…The carp were randomly divided into 27 treatment groups and a blank group, with 10 carp in each group. The carp were then immersed individually in a solution of 75 mg/L of eugenol for 15 min, and the medicine bath administration was performed according to the literature ( 19 , 20 ). The appropriate eugenol was first diluted in ethanol (1:10, v/v) and then added to water to keep the immersion concentration of eugenol at 20, 35, and 75 mg/L.…”