Sea Cucumber Body Vesicular Syndrome Is Driven by the Pond Water Microbiome via an Altered Gut Microbiota.

Apostichopus japonicus (sea cucumber) is one of the most valuable aquaculture species in China; however, different diseases can limit its economic development. Recently, a novel disease, body vesicular syndrome (BVS), was observed in A. japonicus aquaculture. Diseased animals displayed no obvious phenotypic characteristics; however, after boiling at the postharvest stage, blisters, lysis, and body ruptures appeared. In this study, a multiomics strategy incorporating analysis of the gut microbiota, the pond microbiome, and A. japonicus genotype was established to investigate BVS. Detailed analyses of differentially expressed proteins (DEPs) and metabolites suggested that changes in cell adhesion structures, caused by disordered fatty acid β-oxidation mediated by vitamin B5 deficiency, could be a putative BVS mechanism. Furthermore, intestinal dysbacteriosis due to microbiome variations in pond water was considered a potential reason for vitamin B5 deficiency. Our BVS index, based on biomarkers identified from the A. japonicus gut microbiota, was a useful tool for BVS diagnosis. Finally, vitamin B5 supplementation was successfully used to treat BVS, suggesting an association with BVS etiology. IMPORTANCE Body vesicular syndrome (BVS) is a novel disease in sea cucumber aquaculture. As no phenotypic features are visible, BVS is difficult to confirm during aquaculture and postharvest activities, until animals are boiled. Therefore, BVS could lead to severe economic losses compared with other diseases in sea cucumber aquaculture. In this study, for the first time, we systematically investigated BVS pathogenesis and proposed an effective treatment for the condition. Moreover, based on the gut microbiota, we established a noninvasive diagnostic method for BVS in sea cucumber.