Determination of toxicity and mean lethal concentration (LC50) of Eugenol on Barbus sharpeyi

Nowadays, the use of medicinal plants and their replacement with hazardous chemicals is increasing in aquaculture industry. One of these medicinal plants is Clove oil extract, mainly used for decreasing stress, anesthesia and sedation in aquaculture industry. Eugenol is a medicinal component derived from clove oil. The aim of the present study was to investigate toxicity effects and mean lethal concentration (LC50) of eugenol on Barbus sharpeyi. Barbus sharpeyi fingerlings (average weight: 5±1 gr) were selected and transferred from Shahid Maleki hatchery to fisheries laboratory of Khorramshahr University of Marine Sciences and Technology. After adaptation, fish were exposed to different concentrations of eugenol (1, 10, 20, 30, 40, 50, 100, 150 and 200 ppm) and behavioural changes were recorded on 0, 1, 12, 24, 48, 72 and 96 hours after exposing to anaesthetic drug, and LC50 was determined. According to the results, the concentrations of 1 ppm and 40 ppm eugenol were identified as the best concentrations for decreasing stress (sedation) and anaesthesia induction in Barbus sharpeyi, respectively. In addition, Eugenol at 200 ppm induced acute toxicity. Based on statistical analysis (Probit analysis), 48-hour LC50 of Eugenol was 22.61±1.76 ppm. Based on the results, Eugenol is an anaesthetic drug with moderate toxicity on Barbus sharpeyi. Therefore, Eugenol appears to be a safe anaesthetic agent for substitution with MS222 for native fish aquaculture.