5.86 0.03 log CFU g1, respectively. In contrast, no increase of
Bacillus spp. concentrationwas observed in the control (Table 3). In
order to confirm at the genus level, the yellow colonies counted on
MYP agar as Bacillus spp. [21] were randomly picked (n ¼ 10) and
subjected for DNA amplification using specific primers. Out of the
10 colonies, 9 and 7 of them showed specific amplification at
595 bp, which were isolated from shrimp fed BM8 and BM5 diets,
respectively (Fig. 1), whereas only 2 colonies were recorded to be
Bacillus spp. in the control (Fig. 1). The bacteriological analysis and
the molecular detection assay clearly showed that B. subtilis strains
L10 and G1 were able to colonize in the GIT after shrimp had
received the diet containing both strains for 8 weeks. In addition,
there were considerable reductions (P < 0.05) of Vibrio spp. in the
GIT of shrimp fed BM8 and BM5 diets at week 4 and 8. Compared to
the control, significant differences (P < 0.05) in the reduction of
Vibrio spp. levels were observed through 8 weeks of experiment,
ranging from 5.53 0.01 to 4.85 0.07 and 5.18 0.1 log CFU g1 in
the shrimp fed BM8 and BM5 diets, respectively