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This study investigated the efficacy of the essential oil (EO) of Aloysia triphylla as an anesthetic for albino and gray strains of silver catfish, Rhamdia quelen. Juveniles were exposed to concentrations between 20 and 800 μL L(-1) EO of A. triphylla to evaluate time of induction and recovery from anesthesia. In another experiment, both strains were divided into four groups such as 0 (control), 30, 40, or 50 μL L(-1) EO and transported for 5 h. The longest time for anesthetic induction and recovery was observed in the albinos. Both strains reached anesthesia in the 100-800 μL L(-1) (11.1-1.24 min) range, without mortality, being 200 μL L(-1) the best response considering time to anesthesia (5.35 min). Albinos transported with all EO concentrations showed higher values of carbon dioxide in the water of transport, but lower levels were observed in grays transported with 40 and 50 μL L(-1) EO when compared to control fish. The same concentrations did not prevent significant whole-body cortisol rise at the end of transport in the albino strain. Juveniles of both strains transported with EO presented lower ion loss to the water compared to control fish. The EO of A. triphylla is an effective anesthetic for albino and gray silver catfish. This EO increases whole-body cortisol levels in the albino strain, but as it reduces net ion loss as in the gray strain, it can be also recommended for transport.

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The aim of this study was to evaluate the anesthesia induction and recovery times of sub-adult and post-larvae white shrimp (Litopenaeus vannamei) that were treated with eugenol and the essential oils (EOs) from Lippia alba and Aloysia triphylla. Oxidative stress parameters in the hemolymph of this species were also analyzed. The concentrations of eugenol, A. triphylla EO and L. alba EO recommended for anesthesia were 200, 300 and 750 μL L(-1) for sub-adults and 175, 300 and 500 μL L(-1) for post-larvae, respectively. The concentrations studied during the transport of sub-adults were between 20 and 50 μL L(-1) eugenol, 20-30 μL L(-1)A. triphylla EO and 50 μL L(-1)L. alba EO. For post-larvae, the optimal concentrations for transport were 20 μL L(-1) eugenol and between 20 and 50 μL L(-1)A. triphylla EO. The white shrimp sub-adults that were exposed to A. triphylla EO (20 μL L(-1)) showed increases in their total antioxidant capacities (150%), catalase (70%) and glutathione-S-transferase (615%) activity after 6 h. L. alba EO (50 μL L(-1)) and eugenol (20 μL L(-1)) also increased GST activity (1292 and 1315%) after 6 h, and eugenol (20 μL L(-1)) decreased the total antioxidant capacity (100%). Moreover, concentrations above 30 μL L(-1) for the EOs of A. triphylla and L. alba and 20 μL L(-1) eugenol were effective at inducing anesthesia and improving the antioxidant system against reactive oxygen species (ROS) after 6 h.

There is an increasing demand for inexpensive and safe anesthetics that can reduce fish stress caused by some procedures such as capture and handling. In this context, the present study evaluated the potential of essential oils (EO) of three Brazilian native plants (Hesperozygis ringens, Lippia sidoides and Ocotea acutifolia) as anesthetics for the silver catfish - Rhamdia quelen. Moreover, an analysis was made of the chemical composition of these oils and their influence on stress parameter. EO of H. ringens and O. acutifolia were effective as anesthetics, without behavioral side effects. EO of O. acutifolia (150 µL L-1) promoted an increase in blood glucose level. Regarding to the composition, pulegone accounts for 96.63% of the EO of H. ringens, and caryophyllene oxide amounts to 56.90% of the EO of O. acutifolia. Two chemotypes, thymol and carvacrol (68.40% and 67.89%, respectively) were verified for EO of L. sidoides. Both samples of EO of L. sidoides showed anesthetic activity in silver catfish, but exposure also caused loss of mucus and mortality. Thus, only the EO of H. ringens and O. acutifolia are advised for anesthetic use

Anesthesia of silver catfish with eugenol: time of induction, cortisol response and sensory analysis of fillet Anestesia de jundiás com eugenol: tempo de indução, resposta ao cortisol e análise sensorial do filé

This study evaluated extracts of Condalia buxifolia as anesthetics for the silver catfish Rhamdia quelen. The effectiveness of eugenol and of the methanolic extract (ME) of C. buxifolia during the transport of this species was also assessed. Fish of two different weights (1.50±0.02 g and 165.70±22.50 g) were transferred to aquaria containing water with the C. buxifolia ME or with fractions obtained from the ME, such as the n-hexane, dichloromethane, ethyl acetate, n-butane and aqueous fractions, at concentrations from 0-300 μL L C. buxifolia ME. The non-ionized ammonia levels were lower at the end of transport in the groups with the compounds than in that with water alone. Moreover, both compounds decreased the Na + , Cl -, and K + net effluxes; therefore, their addition to the water during transport is advisable because they reduce fish mortality and ion loss.Este estudo investigou extratos de Condalia buxifolia como anestésico para jundiá Rhamdia quelen, e também a eficiência do eugenol e do extrato metanólico (EM) de C. buxifolia para utilização durante o transporte dessa espécie. Peixes de dois diferentes pesos (1,50±0,02 g e 165,70±22,50 g) foram transferidos para aquários contendo água com o EM de C. buxifolia ou frações obtidas a partir do EM (n-hexano, acetato de diclorometano, etil n-butano e aquoso, em concentrações na faixa de 0 -300 μL L

The aim of this study was to identify the times of anesthetic induction and recovery in slender seahorses (Hippocampus reidi) that were exposed to the essential oil of Lippia alba (EO), as well as the efficacy of EO as a stress-reducing agent in the transport of this species. Slender seahorses were placed in 1-L aquaria containing different concentrations of EO (0, 10, 20, 50, 150, ), and after induction, fish were transferred to aquaria that were free of anesthetic to evaluate their recovery time. In an additional experiment, slender seahorses were transported in plastic bags with 15 μL L -1 of EO for 4 or 24 h. The increased concentration of EO proportionally decreased the time required for the induction of anesthesia. EO treatment (15 μL L -1 ) inhibited the increase in blood glucose levels that was provoked by transportation for 4 or 24 h. Transportation for 24 h also decreased the number of lymphocytes and increased the neutrophil count, and these effects were avoided with the addition of EO to the water. These results demonstrate that EO was effective as an anesthetic at concentrations of 10-20 μL L -1 for slight sedation and transport and at 150 μL L -1 for deep anesthesia in the slender seahorse.O objetivo deste estudo foi identificar os tempos da indução e recuperação anestésica em cavalos marinhos (Hippocampus reidi) expostos ao óleo essencial de Lippia alba (OE), assim como a eficácia do OE como um agente redutor de estresse no transporte desta espécie. Os cavalos marinhos foram colocados em aquários contendo 1 litro de água e diferentes concentrações de OE (0, 10, 20, 50, 150, 300 e 450 μL L -1 ), após a indução, os peixes foram transferidos à aquários livre de anestésico para avaliar o tempo de recuperação. Em um outro experimento os cavalos marinhos foram transportados em sacos plásticos contendo 15 μL L -1 do OE por 4 ou 24h. A concentração crescente do OE diminuiu proporcionalmente o tempo exigido para a indução da anestesia. O óleo essencial (15 μL L -1 ) inibiu o aumento nos níveis de glicose sanguínea provocada pelo transporte por 4 ou 24 h. O transporte por 24 h igualmente diminuiu o número de linfócitos e aumentou o número de neutrófilos, estas alterações foram evitadas com o uso do OE na água. Estes resultados demonstram que no cavalo marinho o OE é eficaz para a sedação e transporte na faixa de 10-20 μL L -1 e para a anestesia profunda recomenda-se 150 μL L -1 .