Use of eugenol as an anaesthetic for Geophagus brasiliensis juveniles

Abstract

The eugenol is the active ingredient of clove oil and it has shown to be effective and safe as fish anesthetic. In this study were evaluated the effects of different concentrations of eugenol for anesthesia, recovery time, blood glucose and hematocrit percentage of pearl cichlid (Geophagus brasiliensis) juveniles. Concentrations of 50, 80, 100, 120, 150, 170 and 200 mg L -1 eugenol were evaluated in terms of time to achieve the different stages of anesthesia and recovery in a completely randomized design (CRD) with 12 repetitions. These results were tested using the Kruskal-Wallis test with subsequent Dunn test. The evaluated concentrations had anesthetic action of the deep induction 172.57 ± 25 s (50 mg L -1 ) and the period of full recovery of 516.25 ± 102 s (200 mg L -1 ), with statistical difference between the treatments at all the stages. The eugenol effect on blood glucose and on hematocrit percentage at 0 h after deep anesthesia was evaluated for concentrations of 0; 50; 80; 100; 150; 200 mg L -1 , in a completely randomized design with five replications, and the results were assessed by One-Way ANOVA. Glucose and percentage of hematocrit: no statistically significant differences (P>0.05) were observed for these variables. All concentrations of eugenol showed to be effective as an anesthetic for G. brasiliensis and did not affect the survival, blood glucose and the percentage of hematocrit. To minimize adverse effects and achieve faster recovery is indicate the use of 50-80 mg L -1 of eugenol for pearl cichlid juveniles.Keywords: anesthesia; clove oil; fish; pearl cichlid UTILIZAÇÃO DE EUGENOL COMO ANESTÉSICO EM JUVENIS DE Geophagus brasiliensis RESUMOO eugenol, substância ativa do óleo de cravo, tem demonstrado ser eficiente e seguro como anestésico para peixes. Neste estudo foram avaliados os efeitos de diferentes concentrações de eugenol na anestesia, tempo de recuperação, glicemia e percentual de hematócrito de cará (Geophagus brasiliensis). Concentrações de 50, 80, 100, 120, 150, 170 e 200 mg L -1 de eugenol foram avaliadas em relação aos tempos para atingir os diferentes estágios de anestesia e de recuperação, em desenho inteiramente casualizado (DIC), com 12 repetições. Os resultados foram analisados pelos testes de Kruskal-Wallis e teste Dunn. As concentrações avaliadas produziram ação anestésica em período de indução profunda de 172,57 ± 25 s (50 mg L -1 ) e no período de total recuperação de 516,25 ± 102 s (200 mg L -1 ), com diferença estatística entre os tratamentos para todas as fases avaliadas. Foi avaliado o efeito do eugenol sobre a glicose no sangue e sobre o percentual de hematócrito, em 0 h após anestesia profunda, nas concentrações 0, 50, 80, 100, 150 e 200 mg L -1 , em DIC com cinco repetições, e os resultados avaliados através de ANOVA uma via. Não foram observadas diferenças estatísticas significativas (P>0,05) para glicose e hematócrito. Todas as concentrações de eugenol avaliadas apresentaram eficiência como anestésico para G. brasiliensis e não afetaram a sobrevivência,...

Eugenol and tricaine methanesulfonate as anhestesics for the pearl cichlid

“…No mortalities were observed within 24 hours after the assays despite the exposure of fish to high concentrations of the anesthetics. The same result was observed in Rocha et al (2015), which used eugenol with the same species as the present study. However, post-experiment mortalities have been reported when using tricaine (up to 250 mg L -1 ) to induce anesthesia of zebra fish, guppy and discus (Chambel et al, 2015).…”

“…However, Vidal et al (2008) showed a concentration of 107 mg L -1 as estimated from the regression model for an induction time of one minute, which is lower than the concentration obtained in the present study (217 mg L -1 ). Rocha, Stech, Pinheiro, Pagani, and Sukekava, (2015) evaluated doses between 50 and 200 mg L -1 for pearl cichlids with a mean weight of approximately 17.5 g and in water with a temperature of 22.5°C, and observed that fish were anesthetized almost immediately with 50 mg L -1 of eugenol. The previous study also reported an induction time of 110 s with 150 mg L -1 of eugenol, similar to that of the present study (121.17 s).…”