Effect of oral administration of 1,3-1,6 β-glucans in DWV naturally infected newly emerged bees (Apis mellifera L.)

Abstract

AbstractHoneybee pathogens have an important role in honeybee colony mortality and colony losses, most of them are widely spread and necessitate worldwide solutions to contrast honeybee’s decline. Possible accepted solutions to cope with the spread of honeybee’s pathogen are focused on the study of experimental protocols to enhance the insect’s immune defences. Honeybee’s artificial diet capable to stimulate the immune system is a promising field of investigation as ascertained by the introduction of 1,3-1,6 β-glucans as a dietary supplement. In this work, by collecting faecal samples of honeybees exposed to different dietary conditions of 1,3-1,6 β-glucans (0.5% and 2% w/w), it has been possible to investigate the DWV viral load kinetic without harming the insects. Virological data obtained by a one-step TaqMan RT-PCR highlights the ability of 1,3-1,6 β-glucans to reduce the viral load at 24th day of rearing. Furthermore, results indicated that the diet supplemented with 1,3-1,6 β-glucans was associated with a dose-dependent activation of phenoloxidase. Control group showed a higher survival rate than honeybees exposed to different dietary conditions of 1,3-1,6 β-glucans while no differences have been observed concerning syrup daily consumption.