The aim of this study was to evaluate the efficacy of the waxy extract of jambu flowers, Spilanthes acmella as an anaesthetic for fish, using juvenile tambaqui
as a model. The times to induction and recovery after short-term anaesthesia were evaluated by concentration-response trials and secondary stress responses. Juveniles were placed in aquaria containing five different concentrations of jambu extract (5, 10, 15, 20, 25 mg L−1) and the times of anaesthetic induction and recovery were determined. Sham control fish and fish exposed to ethanol-added water were used as controls. The secondary stress responses of fish following anaesthesia with jambu extract (20 mg L− 1) were investigated through an assessment of whole blood variables: glucose, ions (Na+, K+, and Ca++), osmolality, haematocrit (Htc), haemoglobin (Hb), partial pressures of CO2 (pCO2) and O2 (pO2), bicarbonate concentration (HCO3−), and pH. Deep anaesthesia was observed at all concentrations tested in this study. The use of 20 mg L− 1 of this extract is recommended for rapid induction (< 3 min) and uneventful recovery (< 5 min) from deep anaesthesia; while the concentration of 2 mg L− 1 is sufficient to promote sedation. Only transient changes in secondary stress responses were observed in tambaqui during recovery, with most parameters returning to initial values within 48 h post-anaesthesia. Therefore, the extract of jambu flowers may be considered an efficient anaesthetic for tambaqui and other fish species.
Highlights:
This is the first report of jambu extract being used as an anaesthetic for fish.
All concentrations tested (5–25 mg L−1) induced deep anaesthesia and uneventful recovery in juvenile tambaqui.
Only transient physiological changes were observed in blood during recovery.
Statement of relevance: This is the first study using extract of Jambu, Spilanthes acmella as an anaesthetic for aquatic organisms.
Keywords: Sedation; Brazil cress; Plant extract; Spilanthol; Blood parameters
Personally, I rely on benzocaine. But if you don't have access to benzocaine, I know some of you have used plant extracts before; here's one more potential "tool" for your "toolbox."
Last edited by bekateen on 23 Apr 2016, 05:20, edited 3 times in total.
) during handling. Groups of 10 juveniles were separately subjected to a concentration of EOLA: 0 (control group), 10, 20, 50, 100, 200, 300, or 500 mu L L-1. The plasma cortisol levels were significantly decreased in anesthetized fish 4 h after stress of handling. The plasma glucose levels were significantly increased 1 and 4 h after stress of handling in fish exposed to EOLA. Sensory analysis showed that tasters did not detect differences through a blind test in fillet taste and odor between exposed and non-exposed fish. The ideal concentration to promote the best anesthesia and recovery times and to reduce plasma cortisol 4 h after handling is 500 mu L L-1.
