Size-relative Effectiveness of Clove Oil as an Anaesthetic for Rainbow Trout (Oncorhynchus mykiss Walbaum, 1792) and Goldfish (Carassius auratus Linnaeus, 1758)

Costas Perdikaris,Ioannis Paschos,Konstantina Bitchava,Ageliki Paschou,Evangelia Gouva,Ugwemorubong Ujagwung Gabriel,Cosmas Nathanailides,Fotini Athanasopoulou

doi:10.2754/avb201079030481

Abstract

The purpose of this work was to investigate the size-relative effectiveness of clove oil as an anaesthetic for rainbow trout and goldfish. In total, 128 rainbow trout (Oncorhynchus mykiss) (two groups of 20-23 and 30-33 cm mean fork length) and 160 goldfish (Carassius auratus) (four size groups of 1.5-2.5, 5-7, 11-15 and 20-25 cm) were anaesthetized at different clove oil concentrations of 50, 100, 150 mg·l-1 for trouts and 75, 100, 150 mg·l-1 for goldfish. Rainbow trout exhibited total loss of balance and no response to external stimuli with shorter induction time as dosage increased (120.5 s, 64.4 s and 44.3 s, respectively). Goldfish exhibited total loss of balance and no response to external stimuli after induction time that varied with dosage used and body size of fish. The small fish (1.5-7 cm) exhibited shorter induction time which ranged from 84.28 s at 75 mg·l-1 clove oil to 41.14 s at 150 mg·l-1 clove oil. The larger fish had a longer induction time inversely related to the dosage. Recovery time was longer than induction time in both species. Both species recovered within 6 min after anaesthesia at 150 mg·l-1 clove oil. Clove oil did not produce marked changes (P < 0.05) in the physiological indicators of goldfish compared to the control. However, marked changes (P < 0.05) were exhibited in the haematocrit of treated rainbow trout that also exhibited hyperkalaemia and hyperglycaemia (P > 0.05). For both fish species, clove oil was effective, producing minimum stress and zero mortalities, and can be recommended as an effective anaesthetic.

Highlights

The purpose of this work was to investigate the size-relative effectiveness of clove oil as an anaesthetic for rainbow trout and goldfish
According to the U.S FDA, the constituting ingredients of clove oil are considered safe, but none of them has been approved for fish anaesthesia yet (FDA/CVM, 2009)
Results of the numerous studies on clove oil revealed that effective concentrations for anaesthesia vary with fish body size and water temperature (Oikawa et al 1994; Hoskonen and Pirhonen 2006; Mylonas et al 2005; Zahl et al 2009) with the smaller fish being more responsive than the larger one (Holloway et al 2004; Velisek et al 2005a,b)

Summary

Introduction

The purpose of this work was to investigate the size-relative effectiveness of clove oil as an anaesthetic for rainbow trout and goldfish. Goldfish exhibited total loss of balance and no response to external stimuli after induction time that varied with dosage used and body size of fish. Clove oil has recently been studied as a potential anaesthetic for some ornamental fish (Kaiser et al 2006; Macova et al 2008) and several farmed cold and warm water fish species (Wagner et al 2003; Holloway 2004; Velisek et al 2005a,b; Hajek et al 2006, Gomulka et al 2008). Results of the numerous studies on clove oil revealed that effective concentrations for anaesthesia vary with fish body size and water temperature (Oikawa et al 1994; Hoskonen and Pirhonen 2006; Mylonas et al 2005; Zahl et al 2009) with the smaller fish being more responsive than the larger one (Holloway et al 2004; Velisek et al 2005a,b). Goldfish (Carassius auratus) is a warm water ornamental fish species, which is frequently subjected to anaesthesia for spawning and vaccination and could benefit from the use of clove oil

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Methods

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Conclusion