有毒铜绿微囊藻对鱼和溞的毒性

THE TOXICITY OF MICROCYSTIS AERUGINOSA TO FISHES AND DAPHNIA

用有毒铜绿微囊藻细胞及其从毒细胞中提取的毒素喂养和腹腔注射鱼类，结果表明：（1）微囊藻毒素MCYST－LR对所有实验过的鱼有毒害作用（LD_(50)为110－500μg／kg）．注射毒素24h后，鱼肝电镜超微结构观察均表现出肝损伤．（2）在受控条件下，当用有毒铜绿微囊藻作为食物喂养日鲢和罗非鱼时，鱼类能在以毒藻为唯一食物的环境中生活20d以上．白鲢和罗非鱼粪便的毒性比喂食藻类的毒性分别降低约2—4．5倍，其肝的超微结构现察仍有轻度损伤．（3）在培养液中加入15μg／mLMCYST－LR和用实验室纯培养的铜绿微囊藻作为食物培养枝角类时，均可使它们在48h死亡．以无毒微囊藻培养时则生长不良亦不怀卵，表明它不是枝角类合适的食物．

This study is dealt with the effects of toxic Microcystis aeruginosa and Microcystin (MCYST) on fishes and Daphnia magna by feeding and intraperitoncal injcction. The results suggcsted were as follows:1. MCYST - LR was pernicious to all of the tested fishes. 1) Grass Carp: mean weight was about 10- 12 g. The dosage of injection was about 65 - 300 Ug/kg, LD50, 110 pg/kg; 2) Silver Carp: mean weight 18- 20g, dosage of injection 150- 400pg/kg, LD50, 350μg/kg; 3) Tilapia:mean weight 32 - 30 g, dosage of lnjection 400 - 800μg/kg, LD,, 500μg/mg. Liver injury was discovered by observing fish liver ultrastructure 24hrs after the injection with Microcystins. The liver damage of Grass Carp was more serious than that of thc other two fishes.2. When Silver Carp and Tilapia fed on toxic M. aeruginosa as the only diet, they can be alive for more than 20 days. The toxicity of feces dccreascd 2- 4. 5 times respectively compared with that of M. aeruginosa. The absorption spectra and microscopc observation of the feces of both fishes reflectcd that the ability of digesting and absorbing of toxic algae cell and toxin for Tilapia was greater than that of Silver Carp; both fishes had little liver damage by observing their liver ultrastructure.3. Fed on Microcystis aeruginosa or added with 15μg/mL, MCYST - LR to the medium,Daphnia magna may die 48hrs later. Daphnia magna grew slowly and did not carry cggs when fed on nontoxlc M. aeruginosa 8508, showing that Microcystis was not a sultable food for Daph-nla.