AUTHOR=Sumithra T. G. , Sharma Krupesha S. R. , Gangadharan Suja , Suresh Gayathri , Prasad Vishnu , Amala P. V. , Sayooj P. , Gop Ambarish P. , Anil M. K. , Patil Prasanna Kumar , Achamveetil Gopalakrishnan 

TITLE=Dysbiosis and Restoration Dynamics of the Gut Microbiome Following Therapeutic Exposure to Florfenicol in Snubnose Pompano (Trachinotus blochii) to Aid in Sustainable Aquaculture Production Strategies

JOURNAL=Frontiers in Microbiology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.881275

DOI=10.3389/fmicb.2022.881275

ISSN=1664-302X

ABSTRACT=Information on unintended effects of therapeutic exposure of antibiotics on fish gut microbiome is a vital prerequisite for ensuring fish and environmental health during sustainable aquaculture practices. The present study forms the first report on the impact of florfenicol, a recommended antibiotic for aquaculture, on gut microbiome of snubnose pompano (Trachinotus blochii), a high-value marine aquaculture candidate. Both culture-dependent and independent techniques were applied to identify the possible dysbiosis and restoration dynamics. The results revealed the critical transient dysbiotic events in the taxonomic and functional metagenomic profiles and significant reductions in the bacterial load and diversity measures. More importantly, there was a complete restoration of gut microbiome density, diversity, functional metagenomic profiles, and taxonomic composition within 10-15 days of antibiotic withdrawal, establishing the required period for applying proper management measures to ensure animal and environment health. The observed transient increase in the relative abundance of opportunistic pathogens suggested the need to apply proper stress management measures and probiotics during the period. Simultaneously, the results demonstrated the inhibitory potential of florfenicol against marine pathogens (vibrios) and ampicillin-resistant microbes. The study pointed out the possible microbial signatures of stress in fish and possible probiotic microbes (Serratia sp., Methanobrevibacter sp., Acinetobacter sp., and Bacillus sp.) that can be explored to design fish health improvisation strategies. Strikingly, therapeutic exposure neither caused any irreversible increase in antibiotic resistance nor promoted florfenicol resistant microbes in the gut. The significant transient increase in the numbers of kanamycin-resistant bacteria and abundance of two multidrug resistance encoding genes (K03327 and K03585) in the treated fish gut during the initial ten days post-withdrawal suggested the need for implementing proper aquaculture effluent processing measures during the period, thus helps to reduce the spillover of antibiotic resistant microbes from the gut of the treated fish to the environment. In brief, the paper generates first-hand insights on the implications of florfenicol exposure on the gut microbiome of snubnose pompano, targeting its safe and efficient application. Implementation of mitigation strategies against identified risks during the initial 15 days of withdrawal period is warranted to ensure sustainable production from aquatic animal and ecosystem health perspectives.