The experiment was conducted to investigate the
e¡ects of oral administration of probiotics (Bacillus licheniformis
and Bacillus subtilis) in combination with
prebiotic isomaltooligosaccharide (IMO) on the intestinal
micro£ora and immunological parameters of
Penaeus japonicus and its resistence against Vibrio
alginolyticus. A basal diet was supplemented with 0%
probiotics and prebiotic (control), 108 colony forming
unit (CFU) g 1B. licheniformis and 0.2% IMO (T1),108
CFU g 1 B. subtilis and 0.2% IMO (T2), 108 CFU g 1
B. licheniformis in combination with 108 CFU g 1
B. subtilis and 0.2% IMO (T3). The results showed that
the total bacterial counts signi¢cantly increased
(Po0.05) and Vibrio counts signi¢cantly decreased
(Po0.05) in the intestine of shrimp with supplementation
of dietary synbiotics. Shrimp fed the diet with both
Bacillus probiotics and IMO (T3) produced signi¢cantly
higher immune parameters (phenoloxidase activity,
lysozyme activity and nitric oxide synthase activity
and superoxide dismutase activity) than the control
group (Po0.05). Signi¢cant lower cumulative mortality
after challenge with V. alginolyticus was also observed
in shrimp fed diet with both Bacillus probiotics
and IMO (T3) than that in the control group (Po0.05).
The results indicated that the oral administration of
probiotics (B. licheniformis and B.subtilis) and prebiotic
IMO has positive e¡ects on bacterial £ora in P. japonicus
gut, and can activate non-speci¢c immunity of shrimp.
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