Alfiansah Yustian Rovi, Hassenrück Christiane, Kunzmann Andreas, Taslihan Arief, Harder Jens, Gärdes Astrid
Leibniz Centre for Tropical Marine Research (ZMT), Bremen, Germany.
Laboratory of Marine Microbiology, Research Center for Oceanography, Indonesian Institute of Sciences, Jakarta, Indonesia.
Front Microbiol. 2018 Oct 18;9:2457. doi: 10.3389/fmicb.2018.02457. eCollection 2018.
In shrimp aquaculture, farming systems are carefully managed to avoid rearing failure due to stress, disease, or mass mortality, and to achieve optimum shrimp production. However, little is known about how shrimp farming systems affect biogeochemical parameters and bacterial communities in rearing water, whether high stocking densities (intensive system) will increase the abundance of pathogenic bacteria. In this study, we characterized bacterial communities in shrimp ponds with different population densities. Water quality, such as physical parameters, inorganic nutrient concentrations, and cultivable heterotrophic bacterial abundances, including potential pathogenic , were determined in moderate density/semi-intensive (40 post-larvae m) and high density/intensive shrimp ponds (90 post-larvae m), over the shrimp cultivation time. Free-living and particle-attached bacterial communities were characterized by amplicon sequencing of the 16S rRNA gene. Suspended particulate matter (SPM), salinity, chlorophyll a, pH, and dissolved oxygen differed significantly between semi-intensive and intensive systems. These variations contrasted with the equal abundance of cultivable heterotrophic bacteria and inorganic nutrient concentrations. Bacterial communities were dominated by , and . and were the most dominant genera in the particle-attached fractions, while , and were found in the free-living fractions of both systems. Redundancy analysis indicated that among the observed environmental parameters, salinity was best suited to explain patterns in the composition of both free-living and particle-attached bacterial communities ( : 15.32 and 12.81%, respectively), although a large fraction remained unexplained. Based on 16S rRNA gene sequences, aggregated particles from intensive ponds loaded a higher proportion of than particles from semi-intensive ponds. In individual ponds, sequence proportions of and displayed an inverse relationship that coincided with changes in pH. Our observations suggest that high pH-values may suppress populations and eventually pathogenic . Our study showed that high-density shrimp ponds had a higher prevalence of , increased amounts of SPM, and higher phytoplankton abundances. To avoid rearing failure, these parameters have to be managed carefully, for example by providing adequate feed, maintaining pH level, and removing organic matter deposits regularly.
在对虾养殖中，养殖系统会得到精心管理，以避免因应激、疾病或大规模死亡导致养殖失败，并实现对虾的最佳产量。然而，对于对虾养殖系统如何影响养殖水体中的生物地球化学参数和细菌群落，以及高放养密度（集约化系统）是否会增加病原菌的丰度，人们了解甚少。在本研究中，我们对不同种群密度的对虾池塘中的细菌群落进行了特征描述。在对虾养殖期间，测定了中等密度/半集约化（40尾仔虾/立方米）和高密度/集约化对虾池塘（90尾仔虾/立方米）中的水质，如物理参数、无机养分浓度以及可培养的异养细菌丰度，包括潜在病原菌的丰度。通过对16S rRNA基因进行扩增子测序，对自由生活和附着于颗粒上的细菌群落进行了特征描述。半集约化和集约化系统之间的悬浮颗粒物（SPM）、盐度、叶绿素a、pH值和溶解氧存在显著差异。这些变化与可培养异养细菌的丰度和无机养分浓度的相等情况形成对比。细菌群落主要由[具体菌属1]、[具体菌属2]和[具体菌属3]主导。[具体菌属4]和[具体菌属5]是附着于颗粒部分中最主要的菌属，而[具体菌属6]、[具体菌属7]和[具体菌属8]则在两个系统的自由生活部分中被发现。冗余分析表明，在所观察到的环境参数中，盐度最适合解释自由生活和附着于颗粒上的细菌群落组成模式（分别为：15.32%和12.81%），尽管仍有很大一部分无法解释。基于16S rRNA基因序列，集约化池塘中的聚集颗粒比半集约化池塘中的颗粒负载了更高比例的[某种菌]。在各个池塘中，[具体菌属9]和[具体菌属10]的序列比例呈现出与pH值变化一致的反比关系。我们的观察结果表明，高pH值可能会抑制[某种菌]种群，最终抑制病原菌[具体菌名]。我们的研究表明，高密度对虾池塘中[某种菌]的患病率更高，SPM含量增加，浮游植物丰度也更高。为避免养殖失败，必须谨慎管理这些参数，例如提供充足的饲料、维持pH水平以及定期清除有机物质沉积物。
