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Innovative Strategies to Combat Bacterial Diseases
The global seafood industry is growing rapidly and contributes economically to a variety of sectors, including fishermen and aquaculture. The UK has a major involvement in the seafood industry, via both import and export. In 2023, the UK imported 611,000 tonnes of sea fish, worth £3.5 billion [1] and exported 336,000 tonnes of sea fish, worth £1.7 billion [1]. With such economic impact, it is imperative to maintain the quality of fish on the market, but disease is a significant challenge facing the seafood industry [2].
One specific example of seafood disease is early mortality syndrome (EMS) or acute hepatopancreatic necrosis disease (AHPND) that occurs in shrimp [2]. Initially identified in 2009, the disease is caused by Vibrio parahaemolyticus EMS strains (VP-EMS), with strain 13-028/A3 having one of the highest pathogenicity rates due to its high concentrations at stationary growth phase [2]. Previous research has suggested that administration of Bacillus subtilis probiotics to shrimp gastrointestinal tracts can combat the pathogenic effects of VP-EMS and protect shrimp from EMS/AHPND [2]. Kuhn et al. studied two such probiotics, one being a single strain of B. subtilis and the other being Plus10, which was a blend of B. amyloliquifaciens, B. megaterium, B. brevis and two B. subtilis strains [2]. The V. parahaemolyticus EMS strain was cultured in VP-EMS glycerol stocks, prepared by inoculating tryptic soy broth supplemented with sodium chloride with the bacterium [2]. After preparing serial dilutions, VP-EMS culture was enumerated using the Whitley WASP Touch and colonies were counted using the ProtoCOL SR [2]. Approximately 500 Pacific white shrimp were treated with the two probiotics via feed and in-tank, then survival was measured after VP-EMS exposure [2]. Both Bacillus probiotics significantly reduced mortality, and efficacy was greater with probiotic-coated feeds [2]. These results provide a helpful guide on how probiotics can be applied to improve shrimp health in aquaculture [2]. Application of these findings could produce economic improvements in the seafood industry by reducing disease [2].
EMS/AHPND in shrimp is one of many diseases associated with seafood production, so this research is arguably the tip of the iceberg, but with increased knowledge and exposure of this topic, it is hoped that more scientists might investigate diseases in seafood.
Written by DWS Microbiologist, Kirsty Mctear
References
- Organisation MM. Fishing industry in 2023 statistics published [Internet]. GOV.UK. 2024. Available from: https://www.gov.uk/government/news/fishing-industry-in-2023-statistics-published
- Kuhn DD, Smith SA, Williams RC, Galagarza ÓA, Thompson M, Drahos DJ, et al. Use of Direct‐Fed Microbes to Enhance Shrimp Resistance to a Vibrio Parahaemolyticus Strain Causing Early Morality Syndrome (EMS). Aquaculture, Fish and Fisheries. 2024 Oct;4(5).
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