Anaesthetic Effect of Propofol on Rainbow Trout (<i>Oncorhynchus Mykiss</i>) in Two Different Concentrations

Abstract

Objective- The study aims to determine efficacy of propofol as an inmersión agent to induce anesthesia in rainbow trout (Oncorhynchus mykiss).<br /> Design- Experimental study.<br /> Animals- 36 healthy rainbow trout<br /> Procedure- Trouts were sorted ramdomly in two groups, 18 fish each one. Both groups were anesthesized by bath, one of them with 2,5 mg/l, the other one at 5 mg/l concentration. During the experiment, basal respiratory rate, partial and total equilibrium loss, time to anesthesia, anaesthesia respiratory rate and manipulation response were recorded.<br /> Results and Conclusion- Induction and recovery times as well as behavioural response were recorded, being significantly affected by propofol concentration (P <0.01). After exposure to 2,5 and 5 mg/l, fishes reached stage 3 anaesthesia in 4,99 ± 1,07 and 2,81 ± 0,71 minutes respectively. Recovery time were 3,59 ± 1,44 for 2,5 mg/l and 7,49 ± 3,02 minutes for 5 mg/l. After the experiment, the fish remained for 48 hours in a pond attached to the unit, without any death. This study, showed the behavioural response of rainbow trout to anaesthesia as well effectiveness of propofol as anaesthetic. Propofol induce safe dose dependent anaesthesia, being useful for different tasks related to the management of culture trout, as it meets the criteria established in aquaculture use.<br /> Clinical relevance- The results of the present work provide data to be used in surgical procedures and containment maneuvers in the different practices performed in fish farming.