Anesthetic Efficacy of Lavender and Lemongrass Essential Oils in Nile Tilapia (Oreochromis niloticus, i-Excel strain) Fry

Abstract

Anesthetics play a crucial role in aquaculture by ensuring the welfare and health of fish, facilitating various procedures, and preventing physical injuries during handling. Recently, plant- based anesthetics for fish are becoming a sustainable alternative to synthetic anesthetics in aquaculture and fisheries research. The present study examined the use of lavender (Lavandula angustifolia) and lemongrass (Cymbopogon citratus) essential oils as anesthetics for Nile tilapia Oreochromis niloticus(i-Excel strain) fry. Fish (average body weight = 0.004 g) were immersed in varying concentrations of 40, 50, 60, 70, and 80 μL L-1 and 30, 40, 50, 60, and 70 μL L-1 for lavender and lemongrass essential oils, respectively. The induction and recovery times were recorded and the best dose was determined based on rapid induction (<3-4 minutes) and quick recovery (<10 minutes). The results indicated that both essential oils exhibit dose-dependent effects on sedation and recovery. Lavender essential oil achieved optimal anesthesia at 60 μL L-1 , with an induction time of 229.3±10.7 seconds and a recovery time of 310.9±16.9 seconds, while lemongrass essential oil induced optimal anesthesia at 30 μL L-1 , with an induction time of 232.5±11.7 seconds and a recovery time of 130.5±8.6 seconds. Both concentrations for both essential oils resulted in 100.0% survival, while higher doses induced faster anesthesia and recovery but decreased survival rates. These essential oils offer cost-effective alternatives to synthetic anesthetics for short-term handling procedures; however, further research on histopathological effects and optimal transport dosages is needed.