Brewers’ Spent Grain as an Alternative Plant Protein Component of Honey Bee Feed

Bee organisms need nutrients to function properly. Deficiencies of any nutrients decrease the condition and shorten the lifespan of insects. Moreover, protein deficiency decreases honey bee queen productivity and increases aggression in bee colonies. All of these aspects affect the efficiency and the economic aspect of beekeeping production. Limited access to sustainable feed sources for bee colonies during the season forces beekeepers to search for new sources of nutrients, particularly protein. The aim of this study was to investigate the potential use of brewers’ spent grain, which is a by-product of beer production, as a source of protein additive in bees’ diet. Two types of brewers’ spent grain were examined: that from light beer and that from dark porter beer. The spent grains, especially porter spent grains, improved the hemolymph protein content compared to bees fed with sugar cake without additives. It did not fully correspond to the protein levels obtained from bees fed cake with the addition of pollen, but it may be a substitute. The studies showed that brewers’ spent grain has the potential to be used as an alternative plant protein component of honey bee feed.