Cultivation of white leg shrimp Litopenaeus vannamei has been faced to unprecedented disease and environmental issues. This study was conducted to determine the effect of heat-killed Lactobacillus plantarum strain L-137 (HK L-137) on growth performance and immune responses of L. vannamei via dietary treatment. Different levels of 20% HK L-137 (LP20) were added into a commercial feed including 0.0g of LP20 kg^-1 of feed (control), 0.1g of LP20 kg^-1, 0.05g LP20 + 5g β-glucan kg^-1 and 10g β-glucan kg^-1. Shrimp (PL12) were fed with these feeds for 90 days in re-circulation 2 m³ tanks at stocking density of 300 ind./tank. The results showed that survival and growth rates of shrimp fed with feed supplemental LP20 were significantly (PVibrio parahemolyticus challenges were increased significantly (PL. vannamei.