Essential oils from Citrus x aurantium and Citrus x latifolia (Rutaceae) have anesthetic activity and are effective in reducing ion loss in silver catfish ( Rhamdia quelen )

Jane Mello Lopes,Bernardo Baldisserotto,Carine De Freitas Souza,Carlos Garrido Pinheiro,Joseânia Salbego,Bianca Schindler,Berta Maria Heinzmann,Jefferson Costa De Siqueira

doi:10.1590/1982-0224-20170152

Jane Mello Lopes, Bernardo Baldisserotto + Show 6 more

Open Access

https://doi.org/10.1590/1982-0224-20170152

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Abstract

ABSTRACT This study investigated the anesthetic effect of the essential oils (EOs) from the peel of Citrus x aurantium (EOCA) and Citrus x latifolia (EOCL) on silver catfish Rhamdia quelen. Fish were exposed to different concentrations of EOCA and EOCL to determine time of anesthesia induction and recovery. Induction of anesthesia was observed in all fish exposed to 400, 600 or 800 μL L−1 EOCA and 300, 400 or 500 μL L−1 EOCL. Another group of fish were exposed for 8 h to 50, 100, or 200 μL L−1 of either EOs. Overall, fish exposed to ethanol and both EOs presented higher ventilatory frequencies (VF) than the control group throughout the 8 h of exposure. Net ion (Na+, K+ and Cl−) effluxes and ammonia excretion were significantly lower in fish exposed to 50, 100 or 200 μL L−1 of either EOs compared to control fish. Mortality was 37% in fish exposed to 200 μL L−1 of either EOs after 8 h. These findings suggest that EOCA and EOCL are useful anesthetics and sedatives for Rhamdia quelen, but their usefulness as alternatives to reduce stress in fish transportation at the lower concentrations tested (50-100 µL L−1) deserves further study.

Highlights

Materials and MethodsAnesthetics have been used to reduce stress effects in animals caused by capture, handling and transportation, avoiding the occurrence of physiological, biochemical and molecular changes (Ross, Ross, 2008; Gressler et al, 2012; Parodi et al, 2014; Benovit et al, 2015; Souza et al, 2017)
Experiment 1: Anesthesia induction and recovery in R. quelen exposed to essential oils of Citrus x aurantium (EOCA) and EOCL
Increasing the concentration of the essential oils (EOs) proportionally decreased the time required for sedation and anesthesia induction, which occurred in all animals at 400–800 μL L−1 EOCA or 300–500 μL L−1 EOCL

Summary

Introduction

Materials and MethodsAnesthetics have been used to reduce stress effects in animals caused by capture, handling and transportation (in this situation, at sedative concentrations), avoiding the occurrence of physiological, biochemical and molecular changes (Ross, Ross, 2008; Gressler et al, 2012; Parodi et al, 2014; Benovit et al, 2015; Souza et al, 2017). Citrus (Rutaceae) includes several species of plants that produce some of the most cultivated fruits in the world, including oranges, bergamots and lemons, which have an appreciable content of essential oil in their peel (Kummer et al, 2013). Brazil is one of the main suppliers of the EOs of orange, lemon and other citrus fruits, with Citrus x aurantium L., Citrus x sinensis and Citrus x latifolia being the species of major commercial importance (Bizzo et al, 2009; Mattos Jr et al, 2010). Sedative and anxiolytic-like effects have been described for the EO obtained from the peel of Citrus x aurantium in rats and mice (Leite et al, 2008; Costa et al, 2013). The literature does not present reports of their anesthetic effects on fish

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