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

Lactic Acid Bacteria: A Probiotic to Mitigate Pesticide Stress in Honey Bee

Using probiotics, especially those containing lactic acid bacteria (LAB), to support honey bee health and alleviate the negative effects of pesticides represents a promising approach for sustainable beekeeping. Probiotics have shown their ability to boost honey bee immune systems, counteract pesticide impacts, and lower disease rates. Bacteria like Lactobacillus and Bifidobacterium have demonstrated their ability to degrade organophosphorus pesticides using phosphatase enzymes. Additionally, these bacteria are resistant to the harmful effects of pesticides and aid in detoxification. Furthermore, supplementing with LAB positively affects colony growth, resulting in increased honey production, improved pollen storage, and higher brood counts. Various methods of delivering probiotics, such as powdered supplements, sucrose syrup, and pollen patties, have been explored, each with its own set of challenges and considerations. Despite making significant progress, further study is still required to fully comprehend the precise interactions between probiotics and the physiology of honey bees, to improve delivery strategies, and to evaluate the wider ecological effects on hive microbiomes. By implementing probiotic strategies in beekeeping practices, we can create stronger and more resilient honey bee colonies that can thrive amidst environmental challenges, thus promoting the sustainability of pollination services.

Evaluation of Combined Use of Protein and Postbiotics Feed Supplements in Honey Beehives in Autumn and Spring

Feed supplementation in beehives is a commonly necessary practice in beekeeping today, to address the many risks the honey bees face, mainly the climate change and times of food scarcity, agricultural pesticides, or pathogens such as Varroa destructor or Nosema ceranae. Protein supplements and postbiotics products have been evaluated in beehives feed, obtaining improvements of the strength and sanitary status, but they have not been tested in combination. In this study, two experiences have been carried out in autumn and spring to check the potential beneficial effect of this combination in the beehives. Two monitoring were carried out, before and after 1 month of the application of products, in order to assess the strength (number of bees, amount of brood, brood survival, and pollen/honey reserves) and sanitary status (V. destructor and N. ceranae infestation levels) of the colonies. Firstly, the results obtained in autumn experience showed a reduction of both pathogens in supplemented group. On the other hand, in spring, the combination of protein and postbiotics enhanced the brood survival and honey yield, and decreased the V. destructor infestation. Thus, the combined use of protein and postbiotics as feed supplements could be an important tool to improve the sanitary status after the cold season, and to increase the strength and production of beehives in spring, unifying the benefits of both supplements.

Probiotic Potential of Enterococcus lactis GL3 Strain Isolated from Honeybee (Apis mellifera L.) Larvae: Insights into Its Antimicrobial Activity Against Paenibacillus larvae

This study aimed to address the need for effective probiotics and antibacterial agents to combat American foulbrood disease in honeybees, caused by Paenibacillus larvae. In the context of declining honeybee populations due to pathogens, we isolated eight lactic acid bacteria (LAB) strains from honeybee larvae (Apis mellifera L.) and evaluated their probiotic potential and inhibitory effects against P. larvae. Methods included probiotic property assessments, such as acid and bile salt resistance, hydrophobicity, auto-aggregation, co-aggregation with P. larvae, antioxidant capacities, osmotolerance to 50% sucrose, and antibiotic susceptibility. Results indicated that the GL3 strain exhibited superior probiotic attributes and potent inhibitory effects on P. larvae. Whole-genome sequencing revealed GL3 to be an Enterococcus lactis strain with genetic features tailored to the honeybee larval gut environment. Pangenome analysis highlighted genetic diversity among E. lactis strains, while molecular docking analysis identified aborycin, a lasso peptide produced by GL3, as a promising inhibitor of bacterial cell wall synthesis. These findings suggested that GL3 was a promising probiotic candidate and antibacterial agent for honeybee health management, warranting further investigation into its in vivo efficacy and potential applications in beekeeping practices.

Molecular Characterization and Phylogenetic Analysis of Honeybee (Apis mellifera) Mite-Borne Pathogen DWV-A and DWV-B Isolated from Lithuania

Deformed wing virus (DWV) is known as one of the main viruses that affect honeybees' health all around the world. The virus has two widespread genotypes, DWV-A and DWV-B (VDV-1), transmitted mainly by V. destructor mites. In this study, we collected honeycombs with covered broods from 73 apiaries in eight Lithuanian regions and initially investigated the prevalence of V. destructor mites. Mites were collected from May to the end of July in 2021 from 124 hives. The prevalence of V. destructor infestations in beehives reached 30% and 63% in investigated apiaries. The presence of DWV-A and DWV-B pathogens in mites and broods was examined by RT-qPCR targeting the CRPV-capsid region. The molecular characterization of the virus in mite samples was based on sequence analysis of the RNA-dependent RNA polymerase (RdRp) region. In addition, leader polypeptide (LP), structural protein (Vp3), Helicase, and RdRp genes were used for phylogenetic characterization of dual infection. The prevalences of DWV-B in mites and broods were 56.5% and 31.5%, respectively, while DWV-A was detected in 12.9% of mite samples and 24.7% of brood samples. Some of the examined mite samples harboured dual virus infections. Our findings showed that bee colonies from the same apiary were not always infected by the same viruses. Some bee colonies were virus-free, while others were highly infected. Phylogenetic analysis of 21 sequences demonstrated the presence of highly variable DWV-B and DWV-A genotypes in Lithuania and possible recombinant variants of the virus. This study represents the first molecular characterization of mite-borne pathogens hosted by honeybees (Apis mellifera) in Lithuania.

Evaluation of Functional Properties of Some Lactic Acid Bacteria Strains for Probiotic Applications in Apiculture

This study evaluates the suitability of three lactic acid bacteria (LAB) strains-Lactiplantibacillus plantarum, Lactobacillus acidophilus, and Apilactobacillus kunkeei-for use as probiotics in apiculture. Given the decline in bee populations due to pathogens and environmental stressors, sustainable alternatives to conventional treatments are necessary. This study aimed to assess the potential of these LAB strains in a probiotic formulation for bees through various in vitro tests, including co-culture interactions, biofilm formation, auto-aggregation, antioxidant activity, antimicrobial activity, antibiotic susceptibility, and resistance to high osmotic concentrations. This study aimed to assess both the individual effects of the strains and their combined effects, referred to as the LAB mix. Results indicated no mutual antagonistic activity among the LAB strains, demonstrating their compatibility with multi-strain probiotic formulations. The LAB strains showed significant survival rates under high osmotic stress and simulated gastrointestinal conditions. The LAB mix displayed enhanced biofilm formation, antioxidant activity, and antimicrobial efficacy against different bacterial strains. These findings suggest that a probiotic formulation containing these LAB strains could be used for a probiotic formulation, offering a promising approach to mitigating the negative effects of pathogens. Future research should focus on in vivo studies to validate the efficacy of these probiotic bacteria in improving bee health.

Prospects of probiotics in beekeeping: a review for sustainable approach to boost honeybee health

Honeybees are vital for global crop pollination, making indispensable contributions to agricultural productivity. However, these vital insects are currently facing escalating colony losses on a global scale, primarily attributed to parasitic and pathogenic attacks. The prevalent response to combat these infections may involve the use of antibiotics. Nevertheless, the application of antibiotics raises concerns regarding potential adverse effects such as antibiotic resistance and imbalances in the gut microbiota of bees. In response to these challenges, this study reviews the utilization of a probiotic-supplemented pollen substitute diet to promote honeybee gut health, enhance immunity, and overall well-being. We systematically explore various probiotic strains and their impacts on critical parameters, including survival rate, colony strength, honey and royal jelly production, and the immune response of bees. By doing so, we emphasize the significance of maintaining a balanced gut microbial community in honeybees. The review also scrutinizes the factors influencing the gut microbial communities of bees, elucidates the consequences of dysbiosis, and evaluates the potential of probiotics to mitigate these challenges. Additionally, it delineates different delivery mechanisms for probiotic supplementation and elucidates their positive effects on diverse health parameters of honeybees. Given the alarming decline in honeybee populations and the consequential threat to global food security, this study provides valuable insights into sustainable practices aimed at supporting honeybee populations and enhancing agricultural productivity.

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.