Probiotic characterization of a novel Bacillus cereus strain fkW8-1-2 isolated from intestine of white crucian carp (Carassius cuvieri)

Microbial infection can pose a great threat to health of farmed fish. This study aimed to investigate the probiotic characteristics of Bacillus cereus strain fkW8-1-2 isolated from intestine of WCC and its anti-biofilm activity against pathogenic bacteria. The strain fkW8-1-2 showed a high resistance to low pH, bile salt and lysozyme during long-term incubation. The strain fkW8-1-2 displayed a gradual increase of cell surface hydrophobicity with various forms of hydrocarbons. The strain fkW8-1-2 showed the remarkable autoaggregation and coaggregation activity with A. hydrophila L3-3 and E. tarda 1l-4. The culture medium (CM) and cell-free supernatants (CFS) of strain fkW8-1-2 at 48 h cultivation could attenuate biofilm formation of A. hydrophila and E. tarda with the maximum inhibition rates. In addition, the intact cells of strain fkW8-1-2 exhibited the strong antioxidant activity for DPPH removal and superoxide anion clearance. These results indicated that strain fkW8-1-2 possessing probiotic characteristics can pose a protective role in health of farmed fish.