Comparison of ethanol and tween 20 as solubilizers in clove oil anesthesia of carassius auratus on anesthetic stages and histopathology

Clove oil is a water-insoluble substance commonly used in fish anesthesia, usually diluted in ethanol. Due to the lipophilic nature of clove oil, the use of ethanol to dissolve it can cause adverse effects such as tissue irritation and stress in fish, necessitating the investigation of alternative dispersing agents. The aim of this study is to determine the effects of using Tween 20, a non-ionic surfactant, instead of ethanol in clove oil anesthesia, on anesthesia induction and recovery phases, as well as its potential histopathological effects on the liver, kidneys, and gills.Materials and MethodsIn this study, a total of 21 Carassius auratus fish were divided into three equal groups of seven fish each. The groups were: Control group with no treatment; Tween 20+clove oil group anesthetized with 100 mg/L clove oil dissolved in 0.1% Tween 20; and an Ethyl alcohol+clove oil group anesthetized with 100 mg/L clove oil prepared by dissolving it in ethyl alcohol.ResultsRecovery times from anesthesia were found to be significantly longer in the Tween 20 group compared to the alcohol group. In our study, hyperemia and focal cellular infiltration in the liver, and hyperemia in the kidneys and gills were observed in the alcohol-clove oil combination. In the Tween 20 group, hyperemia occured less frequently, and histopathological damage was reduced.ConclusionBecause the fish recovers quickly after surgery or measurement and minimizes the risk of post-anesthetic death, the alcohol-clove oil combination offers a clinically safer option for short-term routine procedures; however, due to causing less histopathological damage, the Tween 20+ clove oil formulation suggests that it can be safely used in long and extensive surgical procedures.