Expression of MRJP3 and HSP70 mRNA Levels in Apis mellifera L. Workers after Dietary Supplementation with Proteins, Prebiotics, and Probiotics

SIMPLE SUMMARY: The development of honey bees depends on royal jelly. Some of the main components of this glandular secretion are proteins known as major royal jelly proteins (MRJPs). In addition to these, bees also produce proteins that help balance the body in situations of stress. During periods of food shortage, beekeepers can supplement colony food to maintain the health and productivity of honey bees. Supplementation can be provided with feed that contains, in addition to other components, probiotics and prebiotics, which are important to balance bees’ intestinal microbiota and, consequently, to keep colonies healthy and without food stress. In order to verify if the addition of probiotics and prebiotics in food supplementation is efficient for the health of bees, after supplementation, we analyzed the levels of synthesis of one MRJP and the stress protein HSP70. The results show that, with the addition of probiotics and prebiotics in the supplementation, there was an increase in the synthesis of the analyzed MRJP3 and low synthesis of the stress protein. Therefore, we suggest that these components be added to honey bee supplementation in periods of food shortage, as it will contribute to colony health in apiaries. ABSTRACT: Royal jelly is an essential substance for the development of bees from larval to adult stages. Studies have identified a group of key proteins in royal jelly, denominated major royal jelly proteins (MRJPs). The group currently consists of nine proteins (MRJP1–MRJP9), with MRJP1 being the most abundant and MRJP3 being used as a microsatellite marker for the selection of queens with a greater production of royal jelly. The diet of bees is mostly composed of proteins, and supplementing this intake to encourage a higher production of their primary product is important for producers. It is estimated that, by adding probiotic and prebiotic organisms to their diets, the benefits to bees will be even greater, both for their immune systems and primary responses to stress. Circumstances that are adverse compared to those of the natural habitat of bees eventually substantially interfere with bee behavior. Stress situations are modulated by proteins termed heat shock proteins (HSPs). Among these, HSP70 has been shown to exhibit abundance changes whenever bees experience unusual situations of stress. Thus, we sought to supplement A. mellifera bee colony diets with proteins and prebiotic and probiotic components, and to evaluate the expression levels of MRJP3 and HSP70 mRNAs using qRT-PCR. The results revealed that differences in the expression of MRJP3 can be attributed to the different types of feed offered. Significant differences were evident when comparing the expression levels of MRJP3 and HSP70, suggesting that protein supplementation with pre/probiotics promotes positive results in royal jelly synthesis carried out by honey bee nurses.