虾源蜡样芽孢杆菌D7的生态安全性评价

为了评价蜡样芽孢杆菌菌株D7的生态安全性,分别测定了蜡样芽孢杆菌D7对氨氮、亚硝酸盐、磷酸盐浓度的影响,以及对小球藻、大型蚤、斑马鱼、凡纳滨对虾和草鱼等水生动植物的安全性。研究结果表明,蜡样芽孢杆菌菌株D7浓度≥1×10⁷ cfu·mL^-1时,水中氨氮及亚硝酸盐含量显著降低(P<0.05)。蜡样芽孢杆菌菌株D7浓度≤1×10⁶ cfu·mL^-1时,对氨氮及亚硝酸盐含量无显著影响。蜡样芽孢杆菌菌株D7浓度在10⁴~10⁸ cfu·mL^-1时,水中磷酸盐含量无显著变化。小球藻含量与菌体浓度呈正相关。处理96 h,对大型蚤、斑马鱼和凡纳滨对虾死亡率均无显著影响。以不同细菌剂量(10⁸~10¹² cfu·mL^-1)灌胃草鱼,处理96 h后,未出现草鱼死亡现象。表明虾源蜡样芽孢杆菌D7生态安全性较好,对水体及养殖动物无明显危害。

Ecological safety assessment of Bcillus cereus D7 isolated from shrimp

In order to evaluate the ecological safety of Bacillus cereus D7, the effects of Bacillus cereus D7 on concentration of ammonia nitrogen, nitrite and phosphate were tested. The research of safety on Chlorella vulgaris, Daphnia magna, Danio retio, Penaeus vanmamei and Ctenopharyngodon idella were also carried out. The results showed that Bacillus cereus D7 (≥1×10⁷ cfu·mL^-1) reduced ammonia nitrogen and nitrite concentration significantly (P<0.05). When the concentration of Bacillus cereus D7 was below 1×10⁶ cfu·mL^-1, there were no significant influence on ammonia nitrogen and nitrite concentration. When the concentration of Bacillus cereus D7 was between 10⁴~10⁸ cfu·mL^-1, there was no significant influence on phosphate. Concentration of Chlorella vulgaris showed positive correlation with Bacillus cereus D7. The death rate of Daphnia magna, Danio retio,Penaeus Vanmamei had no significant difference after 96 h treatment. When the concentration of Bacillus cereus D7 was between 10⁸~10¹² cfu·mL^-1, there was no obvious influence on death rate of Ctenopharyngodon idella after 96 h. The results showed that Bacillus cereus D7 could have no adverse effects on water and aquatic animals, which could be used as a kind of ecological safety probiotics.