Could the essential oil of Lippia alba provide a readily available and cost-effective anaesthetic for Nile tilapia (Oreochromis niloticus)?

Abstract

We report the optimal concentration of the essential oil of Lippia alba (EOLA) for the induction and recovery of anesthesia in Nile tilapia (Oreochromis niloticus) 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 µL 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 µL L-1.