盐度调节方式对培养海水养殖生物絮凝系统的影响

Effects of Salinity Regulation Methods on Establishment of Marine Biological Flocculation Culture System

在9个容积为100 L的圆柱形养殖水桶中,用鳗鱼饲料为原料培养絮体,比较了3种盐度调节方式培养盐度为30的生物絮凝系统的启动效率。第一组为盐度直接调节组:试验开始时盐度即调为30;第二组为盐度缓慢调节组:闷曝结束后每日盐度增加5,每3 h增加1度;第三组为淡水驯化组:将培养好的淡水生物絮凝系统,按照盐度缓慢调节组的增加方式增加盐度。启动完成后,监测3个处理组对10 mg/L氨氮的去除效果。结果显示,盐度调至30时,淡水驯化组和盐度缓慢调节组系统中氨氮和亚硝酸盐氮含量先于盐度直接调节组降至低水平。培养期间,盐度缓慢调节组和淡水驯化组的絮体沉降性能较盐度直接调节组好。高通量测序分析结果表明,黄杆菌纲是盐度为30的生物絮凝系统中的优势菌纲,鞘脂杆菌纲是盐度直接调节组系统中的优势菌纲,放线菌纲是淡水驯化组中的优势菌纲。Leptobactrrium和norank_f_Segniliparacea是盐度为30的生物絮凝系统的主要优势菌属。启动完成后3个处理组氨氮的去除效果差异不显著(P>0.05),盐度缓慢调节组最有利于海水生物絮凝系统的构建。

Effects of three salinity addition methods on culture flocs and the start-up efficiency of bioflocculation system were investigated in nine cylindrical aquaculture buckets with a volume of 100 L and with eel feed as raw materials, in which salinity was adjusted to 30 at the beginning of the experiment in the first group, the salinity was increased by 5 degrees every day after the end of the depression, adding 1 degree every 3 hours in the second group, and the salt was added into cultured freshwater biological flocculation system according to the way of adding salt in the second group in the third group. After startup, the removal efficiency of 10 mg/L ammonia nitrogen in three treatment groups was monitored.The results showed that the contents of ammonia nitrogen and nitrite nitrogen in the second and third groups were decreased to low level before the salinity was adjusted to 30 in first group. During the culture period, there was better settleability of flocs in the second and third groups than that in the first group. The high-throughput sequencing revealed that Flavobacteria was the dominant class in the biological flocculation system with salinity of 30, and Sphingobacteria was the dominant class in the flocculation system with initial salinity of 30. Actinomycetes is the dominant class in the biological flocculation system of freshwater culture and redomestication into seawater. Leptobactrrium and norank_f_Segniliparacea were the dominant genus of marine biological flocculation system with salinity of 30.It was concluded that the second salt regulation method was the most beneficial to cultivate marine biological flocculation system combined with the continuous monitoring of the removal effect of ammonia nitrogen in the three treatment groups after start-up, without significant difference(P>0.05).