and lactic acid bacteria (LAB) levels were determined at the start of
trial from 3 specimens from the initial pool of fish. At the end of the
study, three fish were sampled in each tank and starved for 24 h
prior to microbiological sampling. The fish were killed by physical
destruction of the brain and the skin was washed in a solution of
0.1% benzalkonium chloride before opening the ventral surface
with sterile scissor. Intestinal tract samples of fish were removed,
weighed, and suspended in sterile saline [0.85% (w/v) NaCl]. The
suspension, serially diluted to 106 and 0.1 ml of the solution, was
spread in triplicate onto plate count agar (PCA). DeMan, Rogosa and
Sharpe (MRS) were also used to detect lactic acid bacteria (LAB). All
of the plates were incubated at room temperature (25 C) and
examined for 5 days [7,20], and the number of colonies was
counted. Identification of the samples was carried out according to
Bergy’s method [21].