Changes in intestinal bacterial communities are closely associated with shrimp disease severity

Abstract

Increasing evidence has revealed a close association between intestinal bacterial communities and human health. However, given that host phylogeny shapes the composition of intestinal microbiota, it is unclear whether changes in intestinal microbiota structure in relation to shrimp health status. In this study, we collected shrimp and seawater samples from ponds with healthy and diseased shrimps to understand variations in bacterial communities among habitats (water and intestine) and/or health status. The bacterial communities were clustered according to the original habitat and health status. Habitat and health status constrained 14.6 and 7.7 % of the variation in bacterial communities, respectively. Changes in shrimp intestinal bacterial communities occurred in parallel with changes in disease severity, reflecting the transition from a healthy to a diseased state. This pattern was further evidenced by 38 bacterial families that were significantly different in abundance between healthy and diseased shrimps; moderate changes were observed in shrimps with sub-optimal health. In addition, within a given bacterial family, the patterns of enrichment or decrease were consistent with the known functions of those bacteria. Furthermore, the identified 119 indicator taxa exhibited a discriminative pattern similar to the variation in the community as a whole. Overall, this study suggests that changes in intestinal bacterial communities are closely associated with the severity of shrimp disease and that indicator taxa can be used to evaluate shrimp health status.

Advances, challenges, and directions in shrimp disease control: the guidelines from an ecological perspective

“…Conversely, the bacterial balance in shrimp intestines is disrupted by challenge with pathogenic Vibrio harveyi (Rungrassamee et al 2016). In particular, the deviations in intestinal bacterial communities are closely correlated with disease severity in shrimp (Xiong et al 2015b), whereas a recovery of the intestinal bacterial composition (Rungrassamee et al 2016). Collectively, these previous findings illustrate that intestinal bacterial assemblages are indicative of shrimp health status, mirroring what has been observed in human (Clemente et al 2012;Round and Mazmanian 2009).…”

“…By contrast, comparable integration between intestinal bacterial assemblages and shrimp health is only in its infancy with the recent advances in metagenomic technologies (Rungrassamee et al 2016;Xiong et al 2015b). Given that the shrimp intestinal community is dominated by Proteobacteria (Rungrassamee et al 2014;Xiong et al 2015b), as opposed to mammalian intestines that are dominated by Bacteroidetes and Firmicutes (Clemente et al 2012;Lozupone et al 2012), we might expect the relationship between intestinal microbiota with its host to differ from that in the mammalian systems, upon which most attention has been focused. A comprehensive meta-analysis revealed that host phylogeny shapes the composition of the intestinal assemblages, with few free-living environmental bacteria (Sullam et al 2012).…”

“…For example, increased Helicobacter pylori abundance indicates a high potential for gastric adenocarcinomas (Lathrop et al 2011), while a decreased Firmicutes/Bacteroidetes ratio can indicate inflammatory bowel disease (Spor et al 2011). By contrast, comparable integration between intestinal bacterial assemblages and shrimp health is only in its infancy with the recent advances in metagenomic technologies (Rungrassamee et al 2016;Xiong et al 2015b). Given that the shrimp intestinal community is dominated by Proteobacteria (Rungrassamee et al 2014;Xiong et al 2015b), as opposed to mammalian intestines that are dominated by Bacteroidetes and Firmicutes (Clemente et al 2012;Lozupone et al 2012), we might expect the relationship between intestinal microbiota with its host to differ from that in the mammalian systems, upon which most attention has been focused.…”

“…Recently, there is evidence, albeit limited, showing that healthy and diseased shrimp have distinct intestinal bacterial communities (Xiong et al 2015b;Zheng et al 2016). The most common members of healthy communities are known probiotics, while potentially pathogenic species are more frequently isolated from diseased samples (Zheng et al 2016).…”

“…For example, a recent work has found that shrimp populations are generally healthy, when nitrate is 11.58 mg/L (Xiong et al 2015b). In practice, pond water is changed daily to maintain the desired water quality for shrimp growth (Mohanty et al 2014).…”