海洋蛭弧菌类生物DA5对凡纳滨对虾育苗期幼体和水质的影响

Effects of marine Bdellovibrio-and-like organism DA5 on larval survival and water quality in larval rearing of Litopenaeus vannamei

以热灭活的溶藻弧菌Vibrio alginolyticus培养海洋蛭弧菌类生物菌株DA5,将其以高(11500pfu.mL-1)、低(1150pfu.mL-1)两种浓度加入凡纳滨对虾Litopenaeus vannamei育苗用水中,研究了无节幼体培育到糠虾幼体期间DA5对幼体变态和存活、水体中异养细菌和弧菌含量、pH、化学需氧量(COD)和氨氮(NH3-N)含量的影响。结果显示,高浓度DA5可显著提高幼体存活和变态率,并在加入后3d内降低或显著降低水体异养细菌和弧菌含量,而低浓度DA5对试验期间幼体成活、变态及水体异养细菌和弧菌含量均无显著影响。除糠虾幼体Ⅰ—Ⅱ期高浓度处理组水体NH3-N含量有显著升高外,试验期间各组水体pH、COD和NH3-N含量均无显著差异。表明海洋蛭弧菌类生物DA5可作为一种较理想的生物控制因子应用于对虾育苗中。

The authors studied the effects of marine Bdellovibrio-and-like organisms（BALOs） strain DA5,which was cultured from heat-killed Vibrio alginolyticus,on larval survival and water quality from nauplius stage to mysis stage of Litopenaeus vannamei.The results showed that the survival rate and metamorphic rate of mysis larvae treated with high concentration of DA5（11500pfu·mL-1;HC） could be improved visibly,and the amounts of heterotrophs and vibrios in rearing water were reduced or significantly reduced in the first 3 days.However,there were no obvious effects on larval survival and bacterial amount treated with low concentration of DA5（1150pfu·mL-1;LC） during the larval rearing period.There were no significant differences in pH,chemical oxygen demand,and ammonia-N content in water body among the HC,LC,and control groups,except that the ammonia-N content in the HC group at mysis Ⅰ-Ⅱ stage was increased significantly.This study indicated that marine BALOs strain DA5 can be applied in larval rearing of shrimp as a promising biocontrol agent.