Effects of feeding with a protein liquid supplement on productivity, mortality and health of Apis mellifera hives in southwestern Spain.

Colony collapse disorder (CCD) has affected bees worldwide in recent decades, with southwestern Spain being no exception. This disorder is one of the main causes of Apis mellifera mortality and is believed to be caused by environmental, social and sanitary conditions. Dietary supplementation can help to improve some parameters of the general status and sanitary condition of bees, such as infestation by certain recurrent pathogens, including Varroa destructor and Nosema ceranae, by enhancing immune and social response. Thus, the aim of this study was to test a liquid hydrolysed protein supplement on the health and general status of the hive in several apiaries with access to the same natural food and under similar climatic conditions. We selected two groups of ten hives (supplemented by either placebo or protein) from five apiaries where the number of adult bees, amount of brood (open and operculated), honey and pollen reserves, infestation by V. destructor, N. ceranae, deformed wing virus (DWV) and chronic bee paralysis virus (CBPV) were measured. Additionally, we assess the expression of four immune system-related genes and a gene encoding vitellogenin. At the end of this work, treated hives showed a significant increase in open brood and a decrease in V. destructor infestation. Also, these hives showed a significant decrease in the mortality rate after the cold season. Therefore, supplementation with this product improved the health of the hive and could be a promising tool against bee colony loss.

Evaluation of the Potential Effect of Postbiotics Obtained from Honey Bees against Varroa destructor and Their Combination with Other Organic Products.

The Varroa destructor mite infests Apis mellifera colonies and causes significant harm. Traditional treatments have become less effective because of mite resistance development and can also generate residues inside beehives. This study aimed to gauge the efficacy of a beehive-derived postbiotic in reducing V. destructor viability and to explore its synergies with organic compounds. Four lactic acid bacteria (LAB) species, Leuconostoc mesenteroides, Lactobacillus helsingborgensis, Bacillus velezensis, and Apilactobacillus kunkeei, were isolated and tested in a postbiotic form (preparations of inanimate microorganisms and/or their components) via bioassays. L. mesenteroides, L. helsingborgensis, and B. velezensis notably reduced the mite viability compared to the control, and they were further tested together as a single postbiotic product (POS). Further bioassays were performed to assess the impact of the POS and its combinations with oxalic acid and oregano essential oil. The simple products and combinations (POS/Oregano, POS/Oxalic, Oregano/Oxalic, and POS/Oregano/Oxalic) decreased the mite viability. The most effective were the oxalic acid combinations (POS/Oregano/Oxalic, Oxalic/Oregano, POS/Oxalic), showing significant improvements compared to the individual products. These findings highlight the potential of combining organic products as a vital strategy for controlling V. destructor infection. This study suggests that these combinations could serve as essential tools for combating the impact of mites on bee colonies.

Effect of feed supplementation with probiotics and postbiotics on strength and health status of honey bee (Apis mellifera) hives during late spring.

Currently, beekeeping faces many risks, such as deteriorating health of honeybees in hives, which results in high mortality rates, mainly during winter. An important consequence is the emergence/re-emergence of communicable diseases such as varroosis or nosemosis. These diseases jeopardize the continuity of the sector because of the absence of effective treatments and harmful residues that they can be retained on wax or honey. This study aimed to evaluate how feed supplementation with probiotic and postbiotic products derived from lactic acid bacteria affected the strength, dynamic population, and sanitary parameters of honey bees. Three groups of 30 hives were established and fed with feed supplemented with control, probiotic, or postbiotic products, with a total of nine applications over two months in late spring. Two monitoring tests were conducted to evaluate the strength and health status of hives. Hives that consumed postbiotic products enhanced their strength, increased bee population and egg laying of the queen, and maintained their reserves of pollen, whereas these parameters decreased in hives belonging to other groups. Furthermore, although the results suggested a favorable effect of postbiotic products on the trend of N. ceranae infection levels, probiotics showed intermediate results. While awaiting long-term results regarding V. destructor infestation, which showed similar trends in all groups, feed supplementation with postbiotics could be an important tool for beekeepers to enhance the strength and health status of their hives.