Event Abstract

Evaluation of the antimicrobial activity of the intestinal microbiota of Sparus aurata (Linnaeus, 1758)

  • 1 Escola Superior de Turismo e Tecnologia do Mar, Politécnico de Leiria, Portugal
  • 2 Centro de Ciências do Mar e do Ambiente (IPLeiria), Portugal

The production of organisms in aquaculture systems has been increasing exponentially in the last years as to prevent overexploitation of marine resources, a consequence of a massive growth of the global population numbers and rise in consumption of fish protein. Although aquaculture industry allows a faster production of selected organisms, a major problem, faced constantly, is the exposure of individuals to chronical stress and pathogenic organisms, factors responsible for high economical failures in the sector. Most of these pathogens belong to the Vibrionaceae family, which are fought by the extensive use of chemicals and antibiotics, therefore creating more resistant strains while leading to increasing levels of pollution, trough organic matter discharges into the marine environment [1-4]. Considerable investments have been made to discover new compounds with compelling properties, with a major part of the research made, focusing on the use of marine probiotics. These are marine microorganisms, fungi or bacteria, that when consumed benefit the health of the host organism, namely being able of inhibiting the activity of some pathogenic agents [1,2]. Several studies have successfully shown the interesting properties of probiotics obtained from different species of fish. Sparus aurata (Linnaeus, 1758), most commonly known as gilthead seabream, can be found abundantly on the Atlantic shore and is intensively grown in aquaculture systems. The constant exposure of these individuals to a wide range of pathogens, promotes the development of defence mechanisms [1,2]. This study evaluates the antimicrobial activity of the intestinal microbiota of S. aurata against Vibrio alginolyticus, Vibrio harveyi and Vibrio anguillarum, using the Disk-Diffusion method. For this purpose, the intestinal content of gilthead seabream, obtained from the marine environment, was suspended in NaCl solution (1.5%). Bacterial suspensions (100 μL) were spread in Tryptic Soy Agar (TSA) culture medium supplemented with NaCl (1.5%) (VWR) and in selective culture medium Thiosulfate-Citrate-Bile Salts-Sucrose (TCBS agar, VWR). Plates were incubated at 37°C and 30°C, respectively. After an incubation period of 92 hours, 20 colonies with distinct morphology were selected. These were collected and pure colonies were isolated. Colonies were grown in the liquid media previously indicated and placed in a shaking incubator (IKA, Germany). Cells were lysed through sonication, followed by centrifugation for 10 minutes, full speed. The resulting lysates were stored at -20°C. In order to test the pathogen exclusion competence, samples were then added to Mueller-Hinton plates containing one of the three pathogenic agents in study, along with a negative control and a positive control disk (chloramphenicol, 30μg/mL, Oxoid). After incubation for 24 hours the inhibition of pathogen growth wasn’t registered for none of the Vibrio strains. Even though the intestinal microbiota of Sparus aurata didn’t trigger an inhibitory effect on the growth of the pathogenic organisms, more research should be made on this subject, using a more extensive range of pathogenic organisms and samples sources.

Acknowledgements

This study had the support of Fundação para a Ciência e Tecnologia (FCT), through the strategic project UID/MAR/04292/2013 granted to MARE.

References

1. Cruz, P. M., Ibáñez, A. L., Hermosillo, O. A., & Saad, H. C. (2012). Use of Probiotics in Aquaculture. ISRN Microbiology, 2012, 1-13. doi:10.5402/2012/916845
2. Sihag, C., & Sharma, P. (2012). Probiotics: The New Ecofriendly Alternative Measures of Disease Control for Sustainable Aquaculture. Journal of Fisheries and Aquatic Science,7(2), 72-103. doi:10.3923/jfas.2012.72.103
3. World Bank. (2013). Fish to 2030: Prospects for Fisheries and Aquaculture. Agriculture and environmental services discussion paper; no. 3. Washington, DC. © World Bank. https://openknowledge.worldbank.org/handle/10986/17579 License: CC BY 3.0 IGO.
4. Zhou, X., & Wang, Y. (2012). Probiotics in Aquaculture - Benefits to the Health, Technological Applications and Safety. Health and Environment in Aquaculture. doi:10.5772/2903

Keywords: Aquaculture, Probiotics, Antimicrobial activity, Sparus aurata, gilthead seabream, Vibrio alginolyticus, Vibrio harveyi, vibrio anguillarum, Disk-diffusion method

Conference: IMMR'18 | International Meeting on Marine Research 2018, Peniche, Portugal, 5 Jul - 6 Jul, 2018.

Presentation Type: Poster Presentation

Topic: Blue Biotech

Citation: Alves J, Guedes M, Januário A, Baptista T and Afonso C (2019). Evaluation of the antimicrobial activity of the intestinal microbiota of Sparus aurata (Linnaeus, 1758). Front. Mar. Sci. Conference Abstract: IMMR'18 | International Meeting on Marine Research 2018. doi: 10.3389/conf.FMARS.2018.06.00156

Received: 06 May 2018; Published Online: 07 Jan 2019.

* Correspondence: Miss. Joana Alves, Escola Superior de Turismo e Tecnologia do Mar, Politécnico de Leiria, Peniche, Portugal, joana.abr.alves@gmail.com

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