Anesthetic effects and biochemical changes of peppermint essence (Mentha spicata) in snow trout (Schizothorax zarudnyi)

By increasing the aquaculture facilities, using effective anesthetics and introducing new ingredients is so important. In this study,the efficacy of peppermint (Menthaspicata) as an anesthetic for snow trout (Schizothorax zarudnyi) was investigated. The peppermint essence was used for 30 farmed snow trout with mean (±SD) weight 90.97 ± 38.26 g. The fish were divided into five treatments (each consisting of six fish). Four treatments were exposed to peppermint with 200, 250, 350 and 500 mg L-1 concentrations by immersion method. The control group was not exposed to any dose of the anesthetic. The mean time of each anesthetic doses and recovery stages were measured. Results showed that by increasing the peppermint doses, the time of anesthesia were reduced. The minimum and maximum times of total anesthesia were recorded in 500 and 250 mg L-1 with 161.00 ± 83.20 and 88.17 ± 22.52 seconds, while those in 200 mg L-1 was significantly different from the other treatments. The mean recovery time in snow trout in treatment 200 mg L-1 was the lowest (180.00 ± 97.35s) compared to the other treatments. Acute toxicity test indicated that the 96-h LC50 value of peppermint essencewas 119.58 mg L-1. The result of this experiment clearly indicated that peppermint essence in 200 mg L-1 could be used as an effective anesthetic for handling and transport practices of this species.