The study aimed to screen the probiotic potential of the Bacillus subtilis isolated from intensive shrimp ponds and to assess its effect on the whiteleg shrimp (Liptopenaeus vannamei). Based on an initial screening of 83 isolates identified from sediment samples, 13 strains showed antibacterial activity and 3 of them (CM3.1, CM2.2 and TV1.2) were further screened for their ability to control the pathogen Vibrio parahaemolyticus. All three strains exhibited notable amylase, protease and cellulase activities, but the strain CM3.1, identified as B. subtilis CM3.1, showed the highest extracellular activities and thus was used for further studying. The water supplemented with 102 (T1), 103 (T2), and 104 (T3) CFU mL-1 of this strain was significantly reduced in concentrations of the total ammonia nitrogen (TAN) and nitritenitrogen (NO2--N). No significant differences were found between the control and treatment groups in final weight, weight gain and daily weight gain of the shrimp (p>0.05). However, a significant difference in the specific growth rate and survival rate was found between the control and the T3 treatment (pB. subtilis CM3.1 was found to be improved in quality, with lower TAN and NO2--N concentrations, and provided an enhancement of the survival rate and of the specific growth rate of shrimps.