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The effects of Pediiococcus acidilactici and Lactococcus lactis was evaluated on survival rate and some immunological parameters of L. vannamei during three months of cultivations. Treatments included control group, Pediococcus and Lactococcus treatments and probotic treatmentsfed at 1×10⁹ cfu g^-1. The results indicated that probiotics increased the survival rate (P<0.05). The best immune performance was shown in the probiotics treatments; phenoloxidase activity, proteins, and globulin hemolymph showed  significant difference compared to the control treatment (P<0.05), whereas there were no significant influence on lysozyme activity (P≥0.05). In general, pediococcus treatment showed the best performance in enhancing the immune responses and survival rate.