Determination of Mean Lethal Concentration (LC50) and Anaesthetic Effect of Topped Lavender Essential Oil (Lavandula angustifolia) on Common Carp (Cyprinus carpio) Juvenile

In recent years, medicinal plants have become an important option for use in aquaculture industry. This study was conducted to determine mean lethal concentration (LC50) and investigated the anesthetic effect of Topped lavender essential oil (Lavandula angustifolia) on common carp (Cyprinus carpio) juveniles. Mean lethal concentration of essential oil was calculated based on the OECD (Organization Economic Cooperation and Development) standard in static system. For determining LC50, 150 common carp juveniles with mean body weight of 26.96 ± 1.98 g were used in 6 groups and one control group and each group with three replications (7 juveniles were used for each replication). After Compatibility period (about 2 weeks), juveniles were exposed to different concentrations including 71.12, 72.11, 73.11, 74.13, 75.16 mg/l that were calculated by logarithmic formula. Juvenile behavioral changes and mortality were recorded in the time period at 24, 48, 72 and 96 hours after exposed to Topped lavender essential oil. Determination of Topped lavender essential oil anesthetic effect was done in 6 groups (with 3 replicates), as 10 fish exposed to increasing concentrations including 0 (control), 160, 165, 170, 175 and 180 mg/l. Mean lethal concentration (LC50) after 96 hours was obtained 99.70 mg/l. The lowest time for completion of anesthesia (stage 3 anesthesia) was obtained at a concentration of 170 mg/l with 3.74± 0.35 min and the full recovery of this concentration was obtained at 3.91±0.55 min. The results showed that the best anaesthetic concentration of Topped lavender essential oil was 170 mg/l. It seems that Topped lavender essential oil could be used as anesthetic agent