Aeromonas hydrophila was obtained from the Aquatic
Animal Health and Management Division, CIFE
cultured in nutrient broth (composition: Peptic
digest of animal tissue: 5 g L
1, Nacl: 5 g L
1,
Beef extract: 1.5 g L
1, Yeast extract: 1.5 g L
1,
Final pH at 25°C: 7.4 0.2) for 24 h at 37°C.
The cultures were centrifuged at 3000 g for
10 min. The supernatants were discarded and the
pellets were resuspended in phosphate buffered saline
(PBS, pH 7.4) and the OD of the solution was
adjusted to 0.5 at 456 nm which corresponded to
1 9 107cells mL
1. These bacterial suspensions
were serially diluted with PBS and used for the
challenge experiment