Objectives The influence of commercial helium–oxygen saturation diving on divers’ gut microbiotas was assessed to provide dietary suggestion.
Methods Faecal samples of 47 divers working offshore were collected before (T1), during (T2) and after (T3) saturation diving. Their living and excursion depths were 55–134 metres underwater with a saturation duration of 12–31 days and PaO2 of 38–65 kPa. The faecal samples were examined through 16S ribosomal DNA amplicon sequencing based on the Illumina sequencing platform to analyse changes in the bacteria composition in the divers’ guts.
Results Although the α and β diversity of the gut microbiota did not change significantly, we found that living in a hyperbaric environment of helium–oxygen saturation decreased the abundance of the genus Bifidobacterium, an obligate anaerobe, from 2.43%±3.83% at T1 to 0.79%±1.23% at T2 and 0.59%±0.79% at T3. Additionally, the abundance of some short-chain fatty acid (SCFA)-producing bacteria, such as Fusicatenibacter, Faecalibacterium, rectale group and Anaerostipes, showed a decreased trend in the order of before, during and after diving. On the contrary, the abundance of species, such as Lactococcus garvieae, Actinomyces odontolyticus, Peptoclostridium difficile, Butyricimonas virosa, Streptococcus mutans, Porphyromonas asaccharolytica and A. graevenitzii, showed an increasing trend, but most of them were pathogens.
Conclusions Occupational exposure to high pressure in a helium–oxygen saturation environment decreased the abundance of Bifidobacterium and some SCFA-producing bacteria, and increased the risk of pathogenic bacterial infection. Supplementation of the diver diet with probiotics or prebiotics during saturation diving might prevent these undesirable changes.
- Saturation Diving
- Gut Microbiota
- Next Generation Sequencing
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Contributors Conceptualisation and design: YY and ZJ; Methodology: YY and BP; Investigation and data collection: GZ, WJ, HJ, ZH and XC; Data analysis: YY, HZ and GT; Writing and editing: YY and ZJ; Funding acquisition: ZJ and HG; Implementation assistance: HZ and GT; Supervision: ZJ.
Funding This work was supported by the Research Startup Fund of Nantong University, and the authors were also supported by grants obtained from the National Natural Science Foundation of China (81372131, 81671859 and 81601639), the Natural Science Fund for Colleges and Universities in Jiangsu Province (17KJB340001) and the Foundational Research Fund of Application Key Technology (Nantong, MS12017010-6).
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available in a public, open-access repository.
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