## 4 Conclusions  
Given the great amount of waste and by-products generated by food processing (e.g., the wine-making industry), waste management valorization is essential to ensuring environmental sustainability. The present study evaluated the effect of different doses (0.5, 1, 1.5, 2.5 and 5%) of grape pomace powder (GPP) supplement on the immune system of honeybees, specifically its capacity to control deformed wing virus (DWV). The loads of DWV were lower after feeding with the supplement enriched in phenolic compounds (in the GPP treatments) with respect to the DWV inoculated control (I-DWV). The gene expression determined for the Relish gene showed significant differences for all the GPP doses used with respect to I-DWV, while the treatments showed no significant differences compared to the non-inoculated control (N-DWV), except for the lowest dose (0.5%) on collection day 1. The results allow for the conclusion that the inclusion of encapsulated GPP in the diet of honeybees is a promising alternative to improve bee health because it decreases DWV loads and influences the expression of genes involved in their immune system pathways. This study provides knowledge of the influence of the phenolic compounds of grape pomace on the expression profiles of immune-related genes in honeybees, offering an alternative to waste management from wine production.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/antiox12010054/s1](https://www.mdpi.com/article/10.3390/antiox12010054/s1)]([https://www.mdpi.com/article/10.3390/antiox12010054/s1](https://www.mdpi.com/article/10.3390/antiox12010054/s1)), Figure S1: Klapan-Meiners survival curves for 4 doses of GPP (0.5%; 1%; 2.5%; 5%) in honeybees; Figure S2: Chromatograms of each detection wavelength for GP and GPP analyzed by HPLC-DAD at (a) 280 nm, (b) 320 nm and (c) 360 nm and (d) 520 nm; Table S1: Summary of conditions of the preparation of spray-drying; Table S2: Mean values for loading capacity, powder recovery and entrapment efficiency of powder based on grape pomace obtained by spray-drying.  
**Author Contributions:** Conceptualization, G.P. and M.D.L.; methodology, G.P., M.D.L., D.S. and M.V.; software, G.P.; validation, G.P., M.D.L. and M.V.; formal analysis, G.P. and D.S.; investigation, M.D.L. and D.S.; resources, G.P.; data curation, G.P.; writing--original draft preparation, G.P. and M.D.L.; writing and editing, M.V., M.A. and J.A.C.; visualization, M.V., M.A. and J.A.C.; supervision M.D.L., M.V., M.A. and J.A.C.; project administration, G.P.; funding acquisition, M.D.L. and M.V. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by FONDECYT projects 1201950 and 1211688 (ANID, Chile).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The authors would like to express their gratitude the Doctoral Program in Agronomic Sciences of the University of Concepcion (Chile).  
**Conflicts of Interest:** The authors declare that they have no conflict of interest.