Variation of Microorganisms and Water Quality, and Their Impacts on the Production of Penaeus vannamei in Small-Scale Greenhouse Ponds

To study the factors affecting <i>Penaeus vannamei</i> production in small-scale greenhouse ponds, four ponds in Jiangmen, Guangdong Province, China were selected. This study investigated the variation in the characteristics of bacterial communities and pathogens in pond water and shrimp intestines, as well as water quality factors during the culture stage. Multivariate linear regression equations were used to analyse the potential factors affecting production. The nitrite concentration reached its peak in the mid-culture stage, with a maximum of 16.3 mg·L^-1, whereas total nitrogen and salinity were highest in the late culture stage, reaching 48.4 mg·L^-1 and 26, respectively. The dominant bacteria in the pond water were <i>Marivita</i> and Rhodobacteraceae, whereas in the shrimp intestines, they were <i>Bacillus</i> and <i>Candidatus Bacilloplasma.</i> The nitrifying bacteria in the pond water were dominated by <i>Nitrosomonas</i> and <i>Nitrobacter</i>. Pathogens detected in the pond water included acute hepatopancreatic necrosis disease (AHPND), <i>Enterocytozoon hepatopenaei</i> (EHP), and white spot syndrome virus (WSSV). The counts of EHP and the relative abundance of <i>Ardenticatenales_norank</i> and <i>Marivita</i> in the pond were the main factors affecting the shrimp production (<i>p</i> < 0.01). This study indicates that establishing optimal bacterial communities, such as <i>Marivita</i>, <i>Nitrobacter</i>, and Rhodobacteraceae, and controlling the counts of EHP and AHPND pathogens is crucial for regulating the pond environment and enhancing production.