Characterization and Protective Properties of Lactic Acid Bacteria Intended to Be Used in Probiotic Preparation for Honeybees (Apis mellifera L.)—An In Vitro Study

Abstract

Lactic acid bacteria (LAB) are widely used probiotics and offer promising prospects for increasing the viability of honeybees. Thus, the probiotic potential of 10 LAB strains was determined, which in our previous studies showed the most potent protective abilities. In the current study, we investigated various properties of probiotic candidates. The tested LAB strains varied in susceptibility to tested antibiotics. Isolates showed high viability in sugar syrups and gastrointestinal conditions. None of the LAB strains exhibited β-hemolytic activity, mutual antagonism, mucin degradation, hydrogen peroxide production capacity, or bile salt hydrolase (BSH) activity. Additionally, the cytotoxicity of LAB cell-free supernatants (CFS) was assessed, as well as the effect of CFS from P. pentosaceus 14/1 on the cytotoxicity of coumaphos and chlorpyrifos in the Caco-2 cell line. The viability of Caco-2 cells reached up to 89.81% in the presence of the highest concentration of CFS. Furthermore, LAB metabolites decreased the cytotoxicity of insecticides (up to 19.32%) thus demonstrating cytoprotective activity. All tested LAB strains produced lactic, acetic, and malonic acids. This research allowed the selection of the most effective LAB strains, in terms of probiosis, for future in vivo studies aimed at developing an ecologically protective biopreparation for honeybees.

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

“…The absence of antagonistic interactions among these strains is promising for their inclusion in a honeybee probiotic supplement, fostering a stable and effective multi-strain product. Few studies have investigated the antagonistic effects of LAB strains intended for probiotics in bees [ 49 , 71 ]. This study supports the use of LAB combinations to enhance honeybee health and resilience.…”

“…This aligns with previous findings [ 76 , 77 ], which suggest that lactobacilli may benefit from osmotic protection in the presence of sucrose, thereby contributing to better survival and highlighting the impact of syrup composition on the survival rates of LAB strains. Additionally, Iorizzo et al [ 78 ] noted that A. kunkeei strains isolated from the digestive tract of honeybees showed tolerance to high sugar concentrations, while Leska et al [ 49 ] tested the viability of ten isolated LAB strains and one reference strain, A. kunkeei DSM 12361, in syrups of varying concentrations of glucose, fructose, or sucrose, and the reported results showed a better survival rate of LAB in the syrup with glucose and fructose without sucrose. In this study, the best survival rates for LAB were observed in syrups with carbohydrate concentrations below 55% for both tested syrups, suggesting commercial syrups might need dilution before being used to administer the probiotic mix.…”

“…After that, the plates were incubated for a further 24 h at 37 °C. Following incubation, the test strain’s growth inhibition zone diameter was determined [ 49 ]. The following standards [ 50 ] were applied in order to compare the antagonistic activity of LAB strains: growth inhibition diameters larger than 11 mm were indicative of strong inhibition (+++), 6–10 mm indicated moderate inhibition (++), 1–5.9 mm indicated weak inhibition (+), and 0 mm indicated no inhibition (−).…”

“…Given the absence of an in vitro gastrointestinal model for honeybees, this test adapted methods from existing studies [ 49 , 51 , 52 ], adjusting the composition of simulated gastric and intestinal juices to match honeybee digestive conditions. The process involved the cultivation of LAB in MRS broth for 24 h, followed by centrifugation at 2300× g for 15 min.…”

Enhancing Antioxidant and Antimicrobial Activities in Bee-Collected Pollen through Solid-State Fermentation: A Comparative Analysis of Bioactive Compounds

“…Lactobacillus plantarum , with its robust fermentative ability and adaptability to different substrates, has been documented to improve the digestibility and nutritional profile of various foods. The fermentation process with L. plantarum and L. acidophilus not only breaks down complex food matrices but also potentially increases the levels of essential amino acids, vitamins, and bioactive peptides, adding to the functional value of BP [ 21 , 22 , 23 , 24 , 25 ]. One of the notable benefits of L. plantarum in fermentation is its capacity to improve the bioavailability of nutrients.…”