Main purpose of this study effects of supplemented Brewer’s yeast (0%, 0.2%, 0.5%, 1% and 2%) on growth, survival and immune responses of Macrobrachium rosenbergii. All diets were isonitrogenous with protein of 38% and lipid of 8%. Prawns with initial body weight (4.29±0.20 g.) and total length (6.54±0.25 cm.) were randomly sampled to rear in 32×52×30 cm³. glass aquaria (with close recirculation water system) at the stocking rate of 6 prawn per aquarium. They were fed to apparent satiation three times for 16 weeks. The results showed that growth of prawn fed with 1% Brewer’s yeast supplemented diet were significantly (p<0.05) higher than those of other treatments. Immune response before challenging the prawn with Vibrio harveyi strain 639 for 4 weeks showed that total hemocyte count and phenoloxidase activity of the prawn fed with 1% Brewer’s yeast were significantly (p<0.05) higher than those of other treatments. Immune response after challenging the prawn with Vibrio harveyi strain 639 for 4 days showed that total hemocyte count and phenoloxidase activity of the prawn fed with 1% Brewer’s yeast were significantly (p<0.05) higher than those of other treatments. Cumulative mortality of prawn fed with 1% Brewer’s yeast (13%±0.5%) was lower than those of other treatments. The study concluded that Brewer’s yeast supplemented for 1% in diet was an optimum rate for promoting growth, survival and immune response in Macrobrachium rosenbergii
