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Advisor(s)
Abstract(s)
In order to meet the food needs of a constantly growing world population, aquaculture emerges as the fastest growing food production sector. However, disease outbreaks due to opportunistic bacterial pathogens cause large losses. Antibacterial chemicals used indiscriminately have resulted in resistant bacteria and antibiotic resistance genes. Ecological solutions such as probiotics are needed. Probiotics are microorganisms introduced into another organism that can have beneficial effects on the host as well as improve the external environment. Actinobacteria are an important biotechnological resource, as they produce a great diversity of secondary metabolites with a high range of bioactivities, including antimicrobial. The aim of this study was to explore the probiotic potential of some marine actinobacteria to prevent aquaculture fish diseases. For this, a screening of antimicrobial activity was performed using agar-based disk diffusion and Minimum Inhibitory Concentration (MIC) assays, against three Gram-negative bacterial fish pathogens: Aeromonas hydrophila, Edwardsiella tarda and Pseudomonas anguilliseptica. A total of 54 out of 103 actinobacterial extracts tested, presented bioactivity against these microorganisms, so that the growth of all three Gram-negative pathogens used was inhibited. The diameter of the inhibition halos varied between 8 and 20 mm. Tested extracts presented MIC values of 1000 µg/ml, except for Isoptericola chiayiensis (500 µg/ml). Microbispora bryophytorum, Isoptericola chiayiensis and Nocardia nova were some of the bacteria with the most promising results. Overall, actinobacteria associated with seaweed proved to be a potential source of probiotics to inhibit pathogens in aquaculture fish.
Description
Keywords
Antimicrobial Aquaculture Marine actinobacteria Probiotics
Citation
Santos, M., Girão, M., Oliveira, R. S., & Carvalho, F. (2022). Actinobacteria as new probiotics for preventing fish diseases in aquaculture. Book of Abstracts of 5th Meeting of Medicinal Biotechnology (5MBtM) and 2nd Iberian Congress on Medicinal Biotechnology, 38. https://paginas.ess.ipp.pt/ebtm/2022/5EBTM_BookOfAbstracts.pdf
Publisher
Escola Superior de Saúde P.Porto