Óleo essencial de Lippia alba como anestésico e antibacteriano para peixes

Abstract

There are some effective anesthetics and antibacterial for fishes, but it is important to search new alternatives of substances easily obtained, of low cost for fish farmers and with no risk to fish and human health. Therefore, this study analyzed the use of essential oil (EO) of Lippia alba as anesthetics, in silver catfish (Rhamdia quelen) and slender seahorse (Hippocampus reidi).To identify time of induction and anesthesia recovery, the fishes were placed in aquaria containing different concentrations of EO and after induction, fish were transferred to anesthetic-free aquaria to evaluate recovery time. Blood collect of the fish for analysis of plasma cortisol (silver catfish) and Blood glucose levels (seahorse). In silver catfish blood was collected 0, 1 and 4 h after anesthesia and air exposure and some epecimens were killed at time 0h for sensorial evaluation of the fillet. In slender seahorses blood was collected begin and after the transport of the 4 our 24 h. The results obtained showed that the EO could be used at concentrations ranging from 100 to 500 mg L−1 to induce anesthesia (stage 4) in silver catfish, as it reduces plasma cortisol when the fish is exposed to air, and does not modify the odor and the flavor of the fillet. In seahorses this EO is effective to induce slight sedation in slender seahorse at 10-20 μL L-1and deep anesthesia at 50 450 μL L-1. Furthermore, 15 μL L-1 of EO in the water of transport inhibits elevation of blood glucose and neutrophils and lymphocytes decrease in slender seahorse, and therefore its use in the transport of this species is suggested.