Abstract: The respiratory rate, anesthetic process, and concentrations of serum cortisol (COR) and glucose(GLU) were determined in largehead hairtail juvenileTrichiurushaumelawith body weight of (43.21±0.52)g anaesthetized by MS-222 at a dose of 10, 20, 40, 60, 80, 100,120, 140, and 160 mg/L in East China Sea at water temperature of (26.0±1.0)℃ to investigate the anesthetic effect of MS-222 on largehead hairtail juveniles. According to the fish behavior characteristics in the final stage of anesthetic and recovery process, the anesthetic process was divided into six periods and the recovery process into four stages. It was found that the final anesthetic degree of 0 was observed at MS-222 concentration of below 20 mg/L, and the final anesthetic degree of 6 at MS-222 concentration of over 80 mg/L in all experimental groups. The required time for narcotic state was found to be decreased and the recovery time increased as the concentration of MS-222 was elevated, with the efficient MS-222 mass concentration of 120-140 mg/L under the experimental conditions. The COR contents were increased and then decreased with the prolonged anesthetic period at MS-222 concentration of 20 mg/L and 40 mg/L, and again decrease at MS-222 concentration of 60 mg/L, with the minimal COR content in the fish anaesthetized by MS-222 at 6 hours, without significant difference (P>0.05). There was low serum GLU content with elapse of anesthetic process, with the minimal value at 6 hours post anesthetic, and without significant difference (P>0.05). In conclusion, it is suggested that the effective mass concentration for largehead hairtail juveniles be 120-140 mg/L of MS-222.
2018, Vol. 33 
