硝酸钠和氯化铵对蠕形康纤虫的毒性影响

Toxic effect of ammonia and nitrogen on Cohnilembus verminus

为探究氨氮胁迫下纤毛虫的毒性效应,试验采用静水生物急性毒性试验法,以养殖水体中常见的病害原生动物盾纤类纤毛虫——蠕形康纤虫(Cohnilembus Verminus)为试验材料,测定了其在硝酸钠和氯化铵两种氮源药物胁迫下的LC50值,并以此为基准开展亚急性毒性试验,测定蠕形康纤虫种群密度、种群生长率和世代时间。结果显示,硝酸钠和氯化铵对蠕形康纤虫的24 h的半致死浓度分别是27.980和3225.970mg/L;48h的半致死浓度分别是27.320和901.600mg/L。在硝酸钠和氯化铵作用下,随着药物浓度升高,蠕形康纤虫最大种群密度和种群生长率均呈现先升高后降低的趋势,世代时间呈现先降低后升高的趋势。研究表明,低浓度氨氮胁迫对蠕形康纤虫生长有促进作用,相对于其他的水生生物,蠕形康纤虫对氨氮耐受性较高。在实际高密度水产养殖中,应关注盾纤类纤毛虫的病害。

In order to explore the toxic effect of ammonia nitrogen stress on ciliates,this study adopted the acute toxicity test method of hydrostatic organisms,and measured the LC50 value of Cohnilembus verminus under the stress of sodium nitrate and ammonium chloride.The results showed that the half lethal concentrations of sodium nitrate and ammonium chloride for 24 hours were 27.980 mg/L and 3225.970 mg/L respectively,and the half lethal concentrations for 48 hours were 27.320 mg/L and 901.600 mg/L respectively.Low concentrations of sodium nitrate and ammonium chloride can promote the growth of C.Verminus.With the increase of drug concentration,the maximum population density and growth rate increased first and then decreased,while the generation time decreased first and then increased.In this experiment,it was found that C.Verminus had a high tolerance to ammonia and nitrogen.Therefore,in the actual high-density aquaculture,the pest of scuticociliatosis should be paid more attention.