This study investigated the effectiveness of eugenol and of the essential oil (EO) of Lippia alba when used in the transport of the silver catfish (Rhamdia quelen). These investigations involved measurements of blood (pH, PvO(2), PvCO(2) and HCO(3) (-)) and water parameters, survival and ionoregulatory balance. Fish (301.24 ± 21.40 g, 28.90 ± 1.30 cm) were transported at a loading density of 169.2 g L(-1) for 4 h in fifteen plastic bags (7 L) divided into five treatments: control, 1.5 or 3.0 μL L(-1) of eugenol and 10 or 20 μL L(-1) of EO of L. alba. The water parameters were measured before (0 h) and after (4 h) transportation. The net Na(+), Cl(-) and K(+) losses were higher in fish from the control treatment compared to the other treatments. The PvO(2), PvCO(2) and HCO(3) (-) increased significantly in all of the treatments at the end of the transport period. In conclusion, based on the water (total ammonia nitrogen) and ionoregulatory indicators determined in the present study, our findings indicate that eugenol and the EO of L. alba are recommended for use in the transport of this species because these anesthetics apparently reduce stress.

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 anesthetic activities of the essential oils (EOs) of Hesperozygis ringens (EOHR) and Lippia alba (EOLA) and their effects in silver catfish (Rhamdia quelen) after anesthesia and recovery were investigated. Fish (32.19 ± 1.24 g) were submitted to one of the following treatments for each EO: basal group, control, or anesthesia (150, 300, or 450 μL L(-1) EO). After that the anesthesia was induced or simulated and the biometric measurements were completed, fish were transferred to anesthetic-free aquaria to allow for recovery. Fish were sampled at 0, 15, 30, 60, and 240 min after recovery. At time 0 of recovery, the ventilatory rate was lower in the groups anesthetized with either EO. In comparison with the basal group, control fish showed an increase in plasma glucose, aspartate aminotransferase (AST), and Na(+) levels and a reduction in Na(+)/K(+)-ATPase activity at 0 min of recovery. Plasma levels of ammonia and Na(+) were lower in the fish anesthetized with EOLA (450 μL L(-1)) and EOHR (all concentrations), respectively, than in the control fish. Additionally, lactate, AST, alanine aminotransferase, K(+) plasma levels, and gill Na(+)/K(+)-ATPase and H(+)-ATPase activities were higher in the fish anesthetized with either EOHR or EOLA than in the control fish. The EOs promoted slight changes in silver catfish that enabled both an adaptive response and the recovery of most of the measured parameters after 240 min regardless of concentration or EO that was used. These findings support the use of EOHR and EOLA as anesthetics for fish.

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

This study investigated the effects of the essential oil (EO) from Lippia alba on biochemical parameters related to oxidative stress in the brain and liver of silver catfish (Rhamdia quelen) after six hours of transport. Fish were transported in plastic bags and divided into three treatments groups: control, 30 µL L for three minutes), except for the control group. Fish transported in bags containing the EO did not have any alterations in acetylcholinesterase, ecto-nucleoside triphosphate diphosphohydrolase and 5'nucleotidase activity in the brain or superoxide dismutase activity in the liver. The hepatic catalase (CAT), glutathione-S-transferase (GST), glutathione peroxidase (GPx), nonprotein thiol and ascorbic acid levels were significantly lower compared to the control group. However, the hepatic thiobarbituric acid-reactive substances, protein oxidation levels and the lipid peroxidation/catalase+glutathione peroxidase (LPO/CAT+GPx) ratio were significantly higher in fish transported with both concentrations of the EO, indicating oxidative stress in the liver. In conclusion, considering the hepatic oxidative stress parameters analyzed in the present experiment, the transport of previously sedated silver catfish in water containing 30 or 40 µL L -1 of EO from L. alba is less effective than the use of lower concentrations.Este estudo investigou os efeitos do óleo essencial (OE) de Lippia alba sobre parâmetros bioquímicos relacionados ao estresse oxidativo em cérebro e fígado de jundiá (Rhamdia quelen), após seis horas de transporte. Os peixes foram transportados em sacos plásticos e divididos em três tratamentos: controle, 30 μL L por três minutos), exceto para o grupo controle. Os peixes transportados em sacos contendo o OE não tiveram alterações na atividade da acetilcolinesterase (AChE), ecto-nucleosídeo trifosfato difosfohidrolase (NTPDase) e 5'nucleotidase, em cérebro ou superóxido dismutase (SOD) no fígado. O tiol não proteico (NPSH), os níveis de ácido ascórbico, catalase (CAT), glutationa-S-transferase (GST) e glutationa-peroxidase (GPx) hepáticos, foram significativamente mais baixos em comparação com o grupo controle. No entanto, as substâncias reativas ao ácido tiobarbitúrico (TBARS), os níveis de oxidação proteica e a taxa de peroxidação lipídica/catalase+glutationa peroxidase (LPO/ CAT+GPx) foram significativamente maiores nos peixes transportados com ambas as concentrações de OE, indicando estresse oxidativo no fígado. Em conclusão, considerando os parâmetros de estresse oxidativo do fígado analisados no presente experimento, o transporte de jundiás previamente sedados em água contendo 30 ou 40 µL L -1 de OE de L.alba é menos efetivo que utilizando concentrações menores.