dietary Spirulina(Spirulina platensis) has immunostimulatory effects on the innate immune system of carp Cyprinus carpio after being fed 1, 3 and 5 days Spirulina enhanced responses of phagocytic activity and superoxide anion production in kidney phagocytic cells… was observed for at least 5 days post treatment. The expression of interleukin (IL)-1β and tumor necrosis factor (TNF)-α genes also increased. the expression of IL-10 gene was decreased. the numbers of Aeromonas hydrophila in the liver and kidney were decreased