Effects of the combination of Lactobacillus helveticus and isomalto-oligosaccharide on survival, gut microbiota, and immune function in Apis cerana worker bees.

The adult worker bees were fed sucrose syrup or sucrose syrup supplemented with Lactobacillus helveticus KM7, prebiotic isomalto-oligosaccharide (IMO), or L. helveticus KM7 combined with IMO. Survival rate, gut microbiota, and gene expression of gut antimicrobial peptides in worker honey bees were determined. Administration of L. helveticus KM7 and IMO significantly increased the survival rate in worker bees relative to bees fed sucrose only. Then, higher concentration of both lactic acid bacteria and Bifidobacterium in the gut and lower counts of gut fungi, Enterococcus, and Bacteroides-Porphyromonas-Prevotella were observed in bees fed the combination of KM7 and IMO compared with control bees. The combination of L. helveticus KM7 with IMO showed a greater or comparable modulating effect on those bacteria relative to either KM7 or IMO alone. Furthermore, the combination treatment of L. helveticus KM7 and IMO enhanced mRNA expression of antimicrobial peptide genes, including Abaecin, Defensin, and the gene encoding prophenoloxidase (PPO) in the gut compared with both control bees and those either L. helveticus KM7 or IMO alone. These results suggest that the combination of L. helveticus KM7 and IMO synergistically modifies the gut microbiota and immunity and consequently improves the survival rate of Apis cerana adult workers.

In vitro Effects of Prebiotics and Synbiotics on Apis cerana Gut Microbiota.

This study aimed to investigate in vitro effects of the selected prebiotics alone, and in combination with two potential probiotic Lactobacillus strains on the microbial composition of Apis cerana gut microbiota and acid production. Four prebiotics, inulin, fructo-oligosaccharides, xylo-oligosaccharides, and isomalto-oligosaccharides were chosen, and glucose served as the carbon source. Supplementation of this four prebiotics increased numbers of Bifidobacterium and lactic acid bacteria while decreasing the pH value of in vitro fermentation broth inoculated with A. cerana gut microbiota compared to glucose. Then, two potential probiotics derived from A. cerana gut at different dosages, Lactobacillus helveticus KM7 and Limosilactobacillus reuteri LP4 were added with isomalto-oligosaccharides in fermentation broth inoculated with A. cerana gut microbiota, respectively. The most pronounced impact was observed with isomalto-oligosaccharides. Compared to isomalto-oligosaccharides alone, the combination of isomalto-oligosaccharides with both lactobacilli strains induced the growth of Bifidobacterium, LAB, and total bacteria and reduced the proliferation of Enterococcus and fungi. Consistent with these results, the altered metabolic activity was observed as lowered pH in in vitro culture of gut microbiota supplemented with isomalto-oligosaccharides and lactobacilli strains. The symbiotic impact varied with the types and concentration of Lactobacillus strains and fermentation time. The more effective ability was observed with IMO combined with L. helveticus KM7. These results suggested that isomalto-oligosaccharides could be a potential prebiotic and symbiotic with certain lactobacilli strains on A. cerana gut microbiota.

In vitro probiotic properties of Pediococcus pentosaceus L1 and its effects on enterotoxigenic Escherichia coli-induced inflammatory responses in porcine intestinal epithelial cells.

This study aimed to evaluate in vitro probiotic characteristics of Pediococcus pentosaceus strain L1 from pickled radish and investigate its impacts on inflammatory responses in porcine intestinal epithelial cells (IEC) to enterotoxigenic Escherichia coli (ETEC) F4+. The abilities of P. pentosaceus L1 to tolerate gastrointestinal conditions and to antagonize ETEC F4+ growth were determined. Adhesion of P. pentosaceus L1 and its effect on ETEC F4+ adhesion to porcine IPEC-J2 IEC were evaluated. Furthermore, the effects of this strain on proinflammatory gene expression and cytokines/chemokine production in porcine IPEC-J2 IEC induced by ETEC F4+ were determined. P. pentosaceus L1 showed good tolerance to the medium adjusted at pH 2.5 and consequently supplemented with 0.3% oxgall. Reduction of ETEC F4+ growth in co-culture with L1 was found. Effective adhesion of L1 to porcine. IPEC-J2 IEC was observed under these conditions. P. pentosaceus L1 decreased the adhesion of ETEC F4+ to IPEC-J2 IEC and the extent of inhibition of ETEC F4+ adhesion depended on the timing of L1 addition. Further analysis revealed down-regulation of expression of ETEC F4+-induced proinflammatory genes encoding interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-8 (IL-8) in IPEC-J2 IEC. Expression of the genes involved in NF-κB pathway, including RELA and NFKB1, were also repressed, as was production of IL-6, TNF-α, and IL-8. These results indicate that P. pentosaceus L1 may have potential as a probiotic for control of ETEC infection in pigs.