Spirulina platensis exposure enhances macrophage phagocytic function in cats

Bronchoalveolar lavage macrophages isolated from cats were cultured on glass coverslips. Macrophages were exposed to a water-soluble extract of Spirulina platensis in concentration range of 0 to 60 mu g per mL for two hours. Spirulina-extract exposure did not cause significant macrophage cytotoxicity over untreated control cultures. Macrophage monolayers from treated and control cultures were incubated with sheep red blood cells (SRBC) as well as viable Escherichia coli. The percentages of phagocytic macrophages for both of these particulate antigens were higher (a two-fold increase in SRBC phagocytosis and over 10% increase in Escherichia coli uptake) in cultures treated with various concentrations of Spirulina-extract. However, the numbers of either types of particles internalized by phagocytic macrophage were not different between the control and treated cultures. These data which showed that Spirulina platensis extract enhances macrophage phagocytic function imply that dietary Spirulina supplementation may improve the disease resistance potential in cats.