根据急性毒性试验，推导了氨基脲在刺参中的半数致死浓度值(LC50)，96 h LC50为3.72 g/L(以盐酸氨基脲计)，95%置信区间为3.43 g/L~4.02 g/L。氨基脲能对刺参呼吸树、肠道和肌肉的组织结构产生一定影响。在1/5 LC50组，呼吸树病变严重，肠道组织基本解体，平滑肌病变紊乱；在1/25 LC50组和1/50 LC50组，呼吸树、肠道和肌肉组织均呈现病变缓慢且逐步积累的现象。刺参对氨基脲的毒性作用表现为毒物兴奋效应，抗氧化酶和神经传导关键酶活性均显示先升高后降低的趋势，即先诱导后抑制，1/5 LC50组刺参中毒反应最为明显。1/25 LC50组超氧化物歧化酶(SOD)、过氧化氢酶(CAT)及乙酰胆碱酯酶(AChE)酶活性最高，其次是1/5 LC50组和1/50 LC50组。中浓度1/25 LC50组呼吸树、肠道和肌肉最大SOD活性值分别是对照组的1.78倍、1.67倍和2.50倍。中浓度1/25 LC50组呼吸树、肠道和肌肉最大CAT活性是对照组的1.87倍、1.96倍和2.04倍。中浓度1/25 LC50组呼吸树、肠道和肌肉最大AChE是对照组的7.86倍、6.24倍和2.86倍。最终均趋于对照组水平，推测可能与刺参免疫疲劳有关。

According to the acute toxicity test, the median lethal concentration (LC50 ) of semicarbazide at 96 h was 3.72 g/L in Apostichopus japonicas (calculated as semicarbazide hydrochloride), with the 95% confidence interval as 3.43 g/L~4.02 g/L. Semicarbazide had an effect on the structure of the respiratory tree, intestines and muscles of Apostichopus japonicas. In the 1/5 LC50 group, respiratory tract lesions were severe and intestinal tissue was disintegrated with disordered smooth muscle lesions. In the 1/25 LC50 and 1/50 LC50 groups, pathological changes in respiratory, intestinal, and muscle tissues were slow but progressive and cumulative. Apostichopus japonicas was excitotoxicitory upon the exposure to the toxicity of semicarbazide, and the activities of antioxidant enzymes and key enzymes associated with neurotransmission increased first and then decreased, that is, induced first and then inhibited, with the 1/5 LC50 group exhibiting the most obvious symptom of poisoning. The 1/25 LC50 group had the highest activities of superoxide dismutase (SOD), catalase (CAT) and acetylcholinesterase (AChE), followed by the 1/5 LC50 group and 1/50 LC50 group. At the medium concentration, the maximum SOD activities of respiratory tree, intestinal and muscle for the 1/25 LC50 group were 1.78 times, 1.67 times and 2.50 times of those for the control group, respectively. The maximum CAT activities of respiratory tree, intestinal and muscle for the 1/25 LC50 group were 1.87 times, 1.96 times and 2.04 times of those for the control group, respectively. The maximum AChE activities of respiratory tree, intestinal and muscle for the 1/25 LC50 group were 7.86 times, 6.24 times and 2.86 times of those for the control group, respectively. In the end, all the enzymatic activities tended to reach the levels similar to those of the control group, which might be related to the immunity and fatigue of Apostichopus japonicas.

中央引导地方科技发展专项（Z135050009017）；山东省现代农业产业技术体系藻类创新团队加工与质量安全控制岗（SDAIT-26-05）；山东省农业重大应用技术创新项目（SF1805301301）