Study on nursing of white leg shrimp (Litopenaeus vannamei) at three different stocking densities (1.000; 2.000 and 3.000 PL/m³) was set up in the tank liners in order to minimize Early Mortality Syndrome (EMS) for grow-out phase. This work was conducted through evaluation of culture medium, survival and growth rates of experimental shrimps. The experimental tanks were designed consisting of the iron frame covered with HDPE sheet and tank volume was 4 m³ (2 m x 2m x 1m). The culture tanks were provided continuous aeration and shrimp postlarvae were fed commercial feed 5 times a day and each density treatment had 3 replicates. After 30 days of experiment, the culture medium in all density treatments were maintained in the suitable ranges for the experimental shrimps i.e. temperature, pH, dissolve oxygen and NH₃ varied in the ranges of 25-28^oC; 7.6-8.1; 5.9-7.1 and 0.05-0.11 mg/L, respectively. Especially, the density of Vibrio sp. in all treatments was varried 4.9×10³ CFU/mL and 11.0×10³ CFU/mL), these numbers may not cause any negative effects on the shrimps in this experiment. Moreover, survivals of shrimp were not statistical differences (p>0.05) in all treatments, and varied in the range of 78.5% - 86.8%. Weight gain of shrimps decreased with increasing stocking density and significant differences (p3 (0.15±0.,08 g) and the poorest growth at stocking density of 3.000 PL/m³ (0.13±0.08 g). Results indicated that nursing L. vannamei postlarvae within 30 days at the stocking densities between 1.000 and 2.000 PL/m³ could obtain the optimal survival and growth rate of shrimp as well as minimized number of Vibrio in the culture medium. ze:13.0pt'>gave the highest values, and statistically differed (PArtemia females in the B37 treatment was superior to the remaining treatments. This indicated that the B37 Bacillus sp.  could be the best probiotic bacteria used as supplemental feed for Artemia.