亚硝酸盐胁迫对尖吻鲈稚鱼消化酶活性的影响

Effect of acute nitrite on digestive enzymes in juvenile Lates calcarifer

目的:分析不同质量浓度亚硝酸盐急性胁迫对尖吻鲈稚鱼(Lates calcarifer)(15日龄)消化酶活性的影响.方法:采用半静水生物测试法,以自然海水(亚硝酸盐质量浓度小于0.03 mg/L)为对照组,开展质量浓度分别为67、200和333 mg/L亚硝酸盐对尖吻鲈稚鱼的急性胁迫实验,分析0、6、12、24、36、48、72和96 h实验鱼消化道中胃蛋白酶、脂肪酶以及淀粉酶活性.结果:不同处理组个体消化酶活性有统计学差异(P<0.05).低、中质量浓度(67、200 mg/L)处理组个体胃蛋白酶活性随时间的变化而呈双波峰变化趋势,高质量浓度(333 mg/L)处理组,个体胃蛋白酶活性先下降后上升;个体脂肪酶活性均因亚硝酸盐的处理而呈波动趋势;个体淀粉酶活性随处理质量浓度升高分别呈“U”型、双波谷和不规则波动趋势,且均显著低于对照组.结论:消化酶活性在亚硝酸盐刺激下具有调节反应.

Objective:To analyze the acute toxicity of nitrite to juvenile Lates calcarifer.Methods:The acute stress test on Lates calcarifer of 15DPH was carried out by semi-static bioassay method at an abrupt change of nitrite concentration from natural seawater to 67,200 and 333 mg/L,respectively.The activities of pepsin,lipase and amylase in the digestive tract of fish were analyzed at 0,6,12,24,36,48,72 and 96 h.Results:The concentration and exposure time of nitrite both influence the activity of digestive enzyme significantly(P<0.05).The changes of pepsin activity in low and medium concentration groups(67 and 200 mg/L)show a double-peaked trend with time.In the high concentration(333 mg/L)group,the pepsin activity decrease initially and then increase;The activity of lipase in each treatment group fluctuate irregularly due to the treatment of nitrite;The amylase activity of each individual change with the increasing of treatment concentration as“U”type,double troughs and irregular fluctuations,and significantly lower than that of the control group.Conclusion:Individuals has a regulatory response on digestive enzyme activity to nitrite stimulation.