Effects of Prebiotics and Probiotics on Honey Bees () Infected with the Microsporidian Parasite .

is a microsporidian fungus that parasitizes the midgut epithelial cells of honey bees, . Due to the role that midgut microorganisms play in bee health and immunity, food supplementation with prebiotics and probiotics may assist in the control of . The dietary fiber prebiotics acacia gum, inulin, and fructooligosaccharides, as well as the commercial probiotics Vetafarm Probotic, Protexin Concentrate single-strain (), and Protexin Concentrate multi-strain (, , , , , , and ) were tested for their effect on spore loads and honey bee survivorship. Bees kept in cages were inoculated with spores and single-dose treatments were administered in sugar syrup. Acacia gum caused the greatest reduction in spore numbers (67%) but also significantly increased bee mortality (62.2%). However, Protexin Concentrate single-strain gave similarly reduced spore numbers (59%) without affecting the mortality. In a second experiment, multiple doses of the probiotics revealed significantly reduced spore numbers with 2.50 mg/mL Vetafarm Probotic, and 0.25, 1.25, and 2.50 mg/mL Protexin Concentrate single-strain. Mortality was also significantly reduced with 1.25 mg/mL Protexin Concentrate single-strain. -inoculated bees fed 3.75 mg/mL Vetafarm Probotic had higher survival than -inoculated bees, which was similar to that of non-inoculated bees, while -inoculated bees fed 2.50 mg/mL Protexin Concentrate single-strain, had significantly higher survival than both -inoculated and non-inoculated bees. Protexin Concentrate single-strain is promising as it can reduce proliferation and increase bee survivorship of infected bees, even compared to healthy, non-infected bees.