The Anaesthesia Effects of MS-222 on Juvenile Squaliobarbus curriculus

Abstract：Anaesthetic has been used in aquaculture to minimize the stress and damage of fish during harvesting，grading，transportation，spawning induction and handling. This study investigated the anaesthetic effect of MS-222 on Juvenile Squaliobarbus curriculus at water temperature26(0.5)℃. According the juvenile behavioral characteristics,the anesthesia process is divided into six stages, while the recovery process is divided into four stages. Experimental results show that the anesthesia time reduced with the increase of mass concentration of MS-222 and the recovery time increased with the increase of mass concentration of MS-222.The most effective anesthetic concentration range from 120mg/L to 180mg/L.At these conditions, the juvenile could reach stage 4 anesthesia within 3 minutes and recover in less than 5 minutes, and had a survival rate of 100% after immersed in the MS-222 solution for 15minutes. In the course of anesthesia, juvenile Squaliobarbus curriculus breathing frequency increased in light anesthesia state, decreased rapidly during deep anesthesia, until the breath cessation. After the juvenile reached stage 5 anesthesia, the fish were taken out for air exposure of 0~18 minutes.When air exposure time within 9 minutes, the recovery time slightly reduced with the extension of air exposure time and all the fish can recovery. When air exposure time in 9 ~ 15 minutes, the recovery time increased and the recovery rate decreased with the extension of air exposure time .When exposed to 18 minutes，all of the experiment fish died. The results indicate that MS-222 as an anaesthetic to juvenile Squaliobarbus curriculus is feasible in terms of the effects that fish can be induced anesthesia rapidly and recovery rapidly with a wide safety concentration ranges without any increasing tolerance by repeated anaesthetization.