漂白粉消毒后对虾养殖源水细菌群落的响应特征研究

漂白粉消毒是凡纳滨对虾养殖源水常见的管控措施, 可有效控制病原菌传播; 然而,消毒会强烈扰动水体微生物群落,但源水细菌群落对漂白粉消毒的响应特征尚未阐明。在室内条件下, 设置高浓度(60 mg/L)和低浓度(20 mg/L)漂白粉消毒源水, 通过高通量测序及荧光定量PCR技术探究消毒后源水细菌群落、病原菌及抗生素抗性基因(ARGs)的动态响应规律。结果显示, 消毒后, 拟杆菌门(Bacteroidota)丰度上升, 高浓度组变形菌门(Proteobacteria)的丰度显著降低; 至第3天, 两组源水的细菌群落组成趋于一致。此外, 漂白粉消毒显著改变了源水的细菌群落结构及共现网络的复杂性。在控制水体病原菌方面, 消毒后病原菌的总丰度降低, 但种类增加, 高浓度漂白粉消毒对病原菌的抑制作用更加显著。漂白粉消毒对ARGs的去除具有选择性, 仅对sul1、floR、cfr、tetQ有一定的去除作用, 且高、低浓度对ARGs的去除无差异。综上, 60 mg/L可以作为漂白粉消毒养殖源水的更好浓度选择。研究结果从微生物生态视角评价了不同浓度漂白粉的消毒作用, 可为对虾养殖生产中的源水管控提供理论支撑。

EFFECTS OF BLEACHING POWDER DISINFECTION FOR SOURCE WATER OF SHRIMP FARMING ON BACTERIAL COMMUNITY

Bleaching powder disinfection is a common practice of source water treatment for shrimp farming to effectively control the spread of pathogens. However, the disinfection can strongly disrupt the aquatic microbial community. At present, the response of bacterial community to bleaching powder have not yet been elucidated. We used bleaching powder in two concentrations (60 mg/L and 20 mg/L) to treat the source water, and analyzed the changes of water physicochemical factors, bacterial community compositions, pathogens, and antibiotic resistance genes (ARGs). Results show that after disinfection, the abundance of Bacteroidetes increased, and the abundance of Proteobacteria decreased significantly in the 60 mg/L group. However, the bacterial community compositions of the two groups recovered and tended to be consistent 3d later. Bacterial community structure and co-occurrence patterns of the source water were significantly changed by the disinfection. The 60 mg/L group showed a more potent inhibitory effect on pathogenic bacteria than 20 mg/L group did. Bleaching powder demonstrated selectivity in eliminating ARGs from source water, showing particular effectiveness against sul1, floR, cfr and tetQ. However, there was no significant difference in the impact on ARGs removal between the two concentration groups. Therefore, the bleaching powder concentration of 60 mg/L was proved a better choice for source water disinfection in shrimp farming. These findings provided valuable insights into the disinfection efficacy of different concentrations of bleaching powder from the perspective of bacterial communities, and offered a theoretical basis for the disinfection of source water to the benefit of shrimp aquaculture.