Modified glucose addition with microalgae can create a healthy and stable rearing microenvironment for Pacific white shrimp (Litopenaeus vannamei)

Abstract

Carbon source addition is an effective microbial management strategy for healthy shrimp growth, but bottleneck problems have emerged in production applications. Beneficial microalgae with functions of capturing carbon dioxide, generating oxygen, absorbing phosphate and recruiting specific bacteria could theoretically modify carbon source addition. However, the implementation effectiveness and underlying microecological mechanism of the combined addition of carbon sources and microalgae remain unknown. Here, we investigated the effects of modified glucose addition with the microalga Nannochloropsis oculata on water quality, shrimp health and rearing water bacterial community. Although purification of the water environment was not achieved, the combined addition of glucose and microalgae significantly improved the shrimp survival rate and immune responses and altered the rearing water bacterial community structure. Network topology analysis indicated that the combined addition limited positive interactions and increased the modularity of the network, which enhanced the bacterial community stability. Partial least squares path modeling (PLS-PM) analysis showed that the bacterial community structure indirectly affected the survival rate of shrimp through bacterial network topological features. Furthermore, comparison of the biomarkers identified by shrimp survival rate-discriminatory importance and the bacterial taxa in the co-occurrence network module related to shrimp survival rate revealed that Rhodobacteraceae taxa recruited by the combined addition of glucose and microalgae might play important roles in maintaining healthy status of shrimp. These results provide a basis for developing novel microbial management strategies for sustainable aquaculture.