Abstract
Increasing evidence has revealed a close association between intestinal bacterial community and hosts health. However, it is unclear whether and what extend Baimang disease alters the intestinal microbiota in mud crab (Scylla paramamosain). Here, we conducted intestinal contents Illumina sequencing of healthy and Baimang diseased mud crab (S. paramamosain) to understand bacterial community variations among health status. In addition, bacterial functional predication was used to investigate whether and how the bacteria variations further change their functions? The phyla of Proteobacteria, Fusobacteria, Cyanobacteria, Tenericutes, Firmicutes, Bacteroidetes, and Spirochaetae constituted over 96.44% of the total intestinal bacteria, with being the dominant taxa. The 7 most significantly different orders, including the increased four orders of Clostridiales, Entomoplasmatales, Bacteroidales, and Mycoplasmatales and the decreased three orders of Vibrionales, Campylobacterales, and Fusobacteriales, accounted for 61.14% dissimilarity, probably being the indicator taxa of Baimang disease. Accordingly, 12 Kyoto Encyclopedia of Genes and Genomes orthologies in level 3 shifted significantly at the diseased crabs. Especially, bacterial secretion system, secretion system, lipopolysaccharide biosynthesis proteins and Vibrio cholerae pathogenic cycle, being related to bacterial virulence, were reduced. In addition, the reduced butanoate metabolism, and induced methane metabolism and one carbon pool by folate were important metabolic processes of probiotic, such as Bacteroides spp. and Clostridium spp., with playing critical roles in host health. This study suggests that Baimang disease coupled altered the intestinal bacterial communities and functions, providing timely information for further analysis the influencing mechanism of Baimang disease in mud crab (S. paramamosain).
Highlights
Gut, the most important digestive organ, is colonized by complex symbiont microbiota with multiple functions critical for host health (Ramírez and Romero 2017; Xiong et al 2018)
Studies have focused on the intestinal microbiota in healthy crabs or intestinal bacterial community assembly driving by growth conditions (Li et al 2007; Chen et al 2015a), little information is available regarding the effect of Baimang disease on the intestinal bacterial community structure and function assembly in mud crab (S. paramamosain), thereby shortening our knowledge of underlying the influencing mechanisms of Baimang disease
Numerous host diseases has been linked to the disruption of intestinal microbial communities (Xiong et al 2015; Zhu et al 2016; Xiong et al 2018); unraveling the bacterial community assembly could help to elucidate the pathogenesis and guide the establishment of new strategies against diseases (Matsuyama et al 2017; Xiong et al 2017)
Summary
The most important digestive organ, is colonized by complex symbiont microbiota with multiple functions critical for host health (Ramírez and Romero 2017; Xiong et al 2018). With the function predication by PICRUSt, Zhu et al (2016) found that the pathways of focal adhesion and disease infection significantly increased in the diseased shrimp, while the antibacterial pathways decreased accompanied with the variety of intestinal microbial composition. These studies suggest that it is important to evaluate the health status of aquaculture organisms by the changes of intestinal microflora. A physiological dysfunction in mud crab (S. paramamosain), is probably caused by dramatic decreased salinity in aquaculture water, plaguing the farmers in southeast China with frequent typhoons and rainstorms (Zheng 2014; Xu et al 2000). Studies have focused on the intestinal microbiota in healthy crabs or intestinal bacterial community assembly driving by growth conditions (Li et al 2007; Chen et al 2015a), little information is available regarding the effect of Baimang disease on the intestinal bacterial community structure and function assembly in mud crab (S. paramamosain), thereby shortening our knowledge of underlying the influencing mechanisms of Baimang disease
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