Black tiger shrimp, Penaeus monodon1 cultivation at field trial in earthen pond, a size of 1,000 m2 were supplemented with Bacillus S11 probiont and commercial feed, to find out its influence on shrimp growth and survival. Live weights of probiotic shrimp were significantly higher (p<0.05) than those of the control group, but non significantly different results among the same group was observed. These results corresponded with the live weights and survival of shrimp after 100 days of culture in duplicated trials in net cages, a size of 2 m2, located in the same pond. Challenge test on shrimp after cultivation for certain time with Vibrio harveyi strain 1526 for 8 days revealed that cumulative mortality of shrimp fed Bacillus S11 was lower in control group non significantly but mortality in probiotic treatment was gradually delayed.
