Evaluation of potential probiotic Bacillus velezensis FS26 against aquaculture pathogens and its ability to utilise prebiotics from Arthrospira platensis A1
Pathogenic bacteria such as Vibrio spp. and Aeromonas spp. frequently cause detrimental effects on aquaculture production. Antibiotics were previously utilised to treat infections, but this led to antibiotic-resistant bacteria emerging in the environment. Probiotics and prebiotics were introduced...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2023
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/111686/1/FBSB%202023%202%20-%20IR.pdf |
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| Summary: | Pathogenic bacteria such as Vibrio spp. and Aeromonas spp. frequently cause
detrimental effects on aquaculture production. Antibiotics were previously
utilised to treat infections, but this led to antibiotic-resistant bacteria emerging in
the environment. Probiotics and prebiotics were introduced to boost the host's
microbiota, disease protection, health condition, growth efficiency, feed
consumption, stress response and overall vigour. Synbiotic is another approach
that should be evaluated intensively to solve the infections problems. However,
probiotic bacteria need to show the ability to utilise prebiotic for synbiotic
preparation. Therefore, this study aims to evaluate the potential probiotic of
selected bacteria against aquaculture pathogens and capability to use prebiotic
from Arthrospira platensis A1. Bacillus velezensis FS26 (Genome accession
number: JAOPEO000000000; 16S rRNA accession number: MZ960133) was
isolated from giant freshwater prawn and showed good probiotic properties
against pathogens in aquaculture through in vitro and in silico studies. Agar well
diffusion assay exhibited the capability of this bacterium through diameter of
inhibition against the pathogenic Aeromonas hydrophila LMG13658, A. veronii
clone DK-A.veronii-27, Vibrio campbellii PKGL21, V. alginolyticus PKS15, V.
parahaemolyticus PKK24 at 23.7, 25, 30, 13.3 and 12.3 mm, respectively. This
bacterium is regarded as harmless based on susceptibility towards 13
antibiotics, γ-haemolytic activity in blood agar and in silico prediction for the lack
of 96 antibiotic resistance genes, pathogenic genes and virulence factors.
Additionally, B. velezensis FS26 has shown the capability to utilise commercial
prebiotics such as lactulose, raffinose and inulin through in silico and in vitro
investigation. The bacterial genome predicted six enzymes that could hydrolyse
glycosidic bonds in prebiotics, such as α-galactosidase, invertase, endolevanase,
β-2,6-fructan-6-levanbiohydrolase and levansucrase. Moreover, using
prebiotics from aquaculture sources such as microalgae could enhance the
palatability of the synbiotic. Hence, water-soluble nondigestible polysaccharide
was extracted from Arthrospira platensis A1 as a prebiotic for B. velezensis
FS26. The structure of water-soluble polysaccharides demonstrated the
presence of α-glycosidic bonds at wavelength 860 nm and water-soluble
compounds at wavelength between 300 to 400 nm through FTIR and UV-VIS
spectroscopy analysis. In the outcome, water-soluble nondigestible
polysaccharide extracted using autoclave exhibited a promising prebiotic activity
towards potential probiotic B. velezensis FS26 by significantly enhance the
bacterial growth on enriched and minimal media at 0.6 x 109 CFU/mL and 7.1 x
109 CFU/mL, compared to control. In conclusion, the findings demonstrate the
capability of probiotic B. velezensis FS26 to inhibit the aquaculture pathogens
and utilise prebiotic from A. platensis A1. |
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