Impact of nutrition on honey bee immunity, gut microbiota and Nosema ceranae infection

CASTELLI, L.; BRANCHICCELA, M.B; GARRIDO P. M.; INVERNIZZI, C; PORRINI, M.P.; ROMERO, H.; SANTOS, E; ZUNINO, P.; ANTÚNEZ K.

Congreso; 46th APIMONDIA; 2019

International Federation of Beekeepers' Associations

Apis mellifera colony loss episodes have been reported losses worldwide and have been associated with parasites and pathogens, pesticides and nutritional stress. Nutritional problems are associated to the increase in monoculture areas and the reduction of pollen availability and/or diversity for bees, among others. These conditions may favor the infection by different pathogens, as the microsporidia Nosema spp. In this study, we examined whether the diet influences bee immunity, gut microbiota and the development of Nosema spp., under laboratory conditions. Newly emerged bees were caged and fed ad libitum with two different diets: Eucalyptus grandis (monofloral bee bread) or a mix of at least 18 botanic families (polyfloral bee bread). The experiment was carried out by triplicate and two independent trials were performed. Bees fed on monofloral and polyfloral diets survived almost 60 days under laboratory conditions. No differences between groups were observed. However, at ten days of feeding, E. grandis bee bread decreased the expression level of vitellogenin and genes involved in social and individual immunity (glucose oxidase, hymenoptaecin, lisozym) compared to polyfloral one. The diet also influenced the abundance of some members of the gut microbiota, as bees fed on E. grandis bee bread showed a lower abundance of Lactid Acid Bacteria (Lactobacillus spp. or Bifidobacterium spp.) and higher abundance of Bartonella apis, compared to bees feed on polyfloral diet. In the second trial, bees subjected to different diets were infected with Nosema ceranae spores, and we found that E. grandis pollen favored the multiplication of the microsporidia. These results suggest that nutrition influences social and individual immunity, the abundance of lactic acid bacteria and the development of Nosema spp., contributing to the understanding of the influence of agriculture intensification on colony health