National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
This work was aimed at isolating AHL degrading bacteria from fish culture pond soil, with abilities appropriate for use as probiotic in aquaculture. The presence of an autoinducer inactivation (aiiA) homologue gene and AHL-inactivation assay showed that BacillusthuringiensisQQ17, which was one among the 20 isolates, could rapidly degrade synthetic C6-HSL in vitro and hampered violacein production by Chromobacterium violaceum. It had excellent biodegrading ability of natural N-AHL produced by Aeromonas hydrophila, suggesting that it can be used as a potential quencher bacterium for inhibiting the virulence of A. hydrophila. The isolate grew well at pH 3.0-7.0, was resistant to high level of bile salts (0-0.9%) and 0.5 % of phenol. QQ17 also exhibited high degree of auto-aggregation and co-aggregation, confirming that it possessed good probiotic attributes. It was susceptible to all the 11 antibiotics tested and exhibited antagonistic activity against A. hydrophila. Gold fish fed diet incorporated with 108 and 1010 CFU/g of the QQ17 for 30 days showed 73.33-83.33% survival when challenged with pathogenic A. hydrophila. The study indicates that the isolate B. thuringiensis QQ17 could be used as a non- antibiotic feed additive in aquaculture to control bacterial diseases.
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