Anesthesia of juvenile Persian sturgeon, Acipenser persicus; Borodin 1897, by peppermint, Mentha piperita, extract - Anesthetic efficacy, stress response and behavior

Anesthesia in large animals such as sturgeons is unavoidable, so in this regard it is important to choice a best anesthetic with lowest side effects in fish.in the present study anesthetic efficacy of mentha, Mentha pipertia, extract was studied in Persian sturgeon, Acipenser persicus, to find if it is a suitable anesthetic for this species. In this regard, the fish were subjected to 300, 500, 750 and 1000 mg L-1 mentha extract, or 150 mg L-1 clove oil, and behavioral response, stress indices, induction and recovery time were recorded. According to the results, the fish exposed to mentha extract showed more severe exciting movements than those exposed to clove oil. No histopathological effects were recorded in gills and kidneys of the fish after anesthesia with both mentha extract and clove oil. Exposure to either 150 mg L-1 clove oil or 750 mg L-1 mentha extract for 3 min resulted in the fish serum cortisol change. Result showed a significant increase in serum cortisol at 6 hrs after anesthesia in both mentioned anesthetic. However, in the fish anesthetized by clove oil, serum cortisol level returned to the pre anesthesia value, at 24 hrs post anesthesia. In the fish anesthetized by mentha extract, a further significant increase in serum cortisol level was observed at 24 hrs after anesthesia. However, it returned to the pre anesthesia level at 72 hrs after anesthesia. At all sampling time, serum cortisol levels of the fish anesthetized by mentha extract were significantly higher than those anesthetized by clove oil. Totally it is concluded that, in Persian sturgeon, use of mentha extract as anesthetic results higher stress compared to clove oil, in the other word, it can be used as a good anesthetic agent but clove oil is better.