In vitro antibacterial activity of ethanol extract of Moringa oleifera’ s leaves was conducted. Disc diffusion assay was used to assess effect of the extract on Vibrio harveyi. The result showed that ethanol extract could inhibit growth of V. harveyi at 6.25 mg/ml. Effect of M. oleifera’ s leaves powder was studied by supplementing to diets on growth, immune response and disease resistant of white shrimp were investigated in vivo. Shrimp were fed diets containing 0, 1, 5 and 10 percent M. oleifera’ s leaves powder after 9 weeks rearing period. Results showed the final weights and growth performance of shrimp fed diets containing 5 and 10 percent M. oleifera’ s leaves powder were significantly higher than those of the control. Survival rates of shrimp fed diets containing 10 percent M. oleifera’ s leaves powder were not different from the control group. However, shrimp raised on diets supplemented with M. oleifera’ s leaves powder 5 and 10 percent showed slightly improvement in immune parameters, such as Total Hemocyte Count and Phenoloxidase activity after 9 weeks of rearing. In a separate experiment, shrimp were challenged with V. harveyi after 6 weeks of diets testing. The results showed the cumulative mortality of shrimp that fed diets containing M. oleifera’ s leaves powder were significantly lower than that of control group. Base on the present data, M. oleifera’ s leaves powder supplemented diet is a potential prophylactic agent against V. harveyi infection in white shrimp.
