不同营养状态下方斑东风螺的镉生物积累及毒性

采用室内模拟方式,研究了方斑东风螺在饥饿及摄食饵料分别为贻贝和沙蚕3种情况下暴露于水体镉(Cd2+,50 μg·L-1)10周后的存活、生长、螺体Cd蓄积及有关毒性效应参数的变化.结果表明:长期饥饿与同时水体Cd暴露降低了方斑东风螺的成活率,且螺体糖原被最大程度动用,摄食有助于螺体抵抗Cd毒性；方斑东风螺肝胰脏DNA受损伤后在摄食状态下随时间延长均有不同程度的自我修复能力,但长期禁食使螺的DNA完整性降低且不能恢复；饥饿引起方斑东风螺体组织萎缩,并导致Cd蓄积与金属硫蛋白(MT)含量升高,摄食螺因体质量增加的稀释作用而具有较低的Cd蓄积与MT含量；摄食贻贝的方斑东风螺较摄食沙蚕有更快的生长率和更低的Cd浓度.表明饥饿加剧了Cd对方斑东风螺的毒性；不同饵料对方斑东风螺的生长有显著影响,并间接影响螺体Cd蓄积、MT诱导和糖原消耗.应用方斑东风螺等海洋腹足类作为环境监测指示种时应考虑栖息地食物丰度和饵料类型等的影响.方斑东风螺高密度工厂化养殖中应注意合理投饵并定期监测海水Cd浓度.

Cadmium bioaccumulation and its toxicity in Babylonia areolata under different nutritional status

An indoor exposure experiment with juvenile Babylonia areolata was conducted to study its survival,growth,cadmium(Cd) accumulation,metallothionein(MT) induction,and glycogen content as well as the DNA integrity of hepatopancreas tissue.The juveniles were starved or fed with mussel(Perna viridis) or clamworm(Perinereis aibuhitensis),and exposed to 50 μg·L-1 of Cd2+ for 10 weeks.Prolonged starvation and simultaneous exposure to Cd reduced the survival rate of B.areolata,and its glycogen was mobilized in great extent.Feeding with P.viridis or P.aibuhitensis helped the B.areolata to combat Cd toxicity and lessen mortality.After exposed to Cd,the damage of the DNA integrity of hepatopancreas tissue for the B.areolata fed with P.viridis or P.aibuhitensis could be recovered with time,but not for the starved B.areolata.Prolonged starvation caused tissue atrophy and led to Cd accumulation and MT increase,while feeding with P.viridis or P.aibuhitensis increased the B.areolata mass and lowered the Cd accumulation and MT level because of the tissue dilution effect.The B.areolata fed with P.viridis had better growth and lower Cd content than that fed with P.aibuhitensis.This study indicated that starvation intensified the toxicity of Cd to B.areolata,while prey type had significant effects on the growth rate of the B.areolata and indirectly affected its Cd accumulation,MT induction,and glycogen consumption.It was suggested that when using gastropods such as B.areolata as the indicator species to monitor marine environmental pollution,it would be necessary to consider the effects of habitat ecological data including food richness and prey type.Moreover,in the high-density cultivation of B.areolata in factory,rational feeding and periodic measurement of Cd concentration in seawater should be made.