Hideaki Takahashi

Aims: To evaluate whether dietary co-supplementation with 1-kestose (Kes) and heat-killed Lactiplantibacillus plantarum FM8 (FM8), collectively termed Kes+FM8, affects survival, growth performance, and intestinal microbiota composition in juvenile abalone (Haliotis discus discus). Study Design: A preliminary, large-scale, controlled hatchery feeding trial with two dietary groups, one tank per treatment, and approximately 10 months of post-supplementation follow-up. Place and Duration of Study: Shizuoka Prefectural Thermal Effluent Utilization Research Center, Omaezaki, Shizuoka, Japan. The 60-day intervention was conducted from June 24 to August 23, 2024, followed by approximately 10 months on a standard diet. Methodology: Juvenile abalone (initial shell length approximately 15 mm; approximately 22,500 per group) received either a control diet or a Kes+FM8-supplemented diet containing 1% Kes and 0.1% heat-killed FM8 for 60 days. Survivor numbers were estimated daily, shell length was assessed on Days 0, 20, 40, 60, and 360, and intestinal microbiota was analysed in visceral tissue samples from nine abalone per group at Day 60 by 16S rRNA gene sequencing. Results: Although both groups experienced a marked mortality event coinciding with elevated seawater temperatures, the number of surviving abalone in the Kes+FM8 group remained higher and was approximately 1.5 times that in the control group at Day 360. Shell length did not differ during supplementation but was greater in the Kes+FM8 group at Day 360 (P < 0.001). At Day 60, the Shannon index was higher (P = 0.024), and microbial community composition differed between groups (PERMANOVA, P ≤ 0.001). The relative abundance of the Shewanella algae group was higher in the Kes+FM8 group. Conclusion: These preliminary findings suggest associations between Kes+FM8 supplementation and survival, growth, and microbiota composition; however, dietary and tank effects could not be distinguished. Replicated tank-level trials including Kes-only and FM8-only groups are needed to evaluate efficacy.

Gut microbiota dysbiosis is implicated in diverse intestinal and systemic disorders, and prebiotics offer a practical strategy to modify host–microbe interactions. This review evaluates 1-kestose as a candidate precision bioactive component by integrating its chemical structure, enzymatic production, gastrointestinal fate, GH32-dependent microbial utilization, human evidence, and qPCR-based response monitoring. Many commercial fructooligosaccharides contain molecules with different degrees of polymerization, complicating structure–function interpretation. In contrast, 1-kestose is a high-purity trisaccharide fructooligosaccharide and the shortest member of the inulin-type fructans. By comparing 1-kestose with long-chain inulin, we examine how fructan chain length may influence colonic fermentation kinetics, substrate availability, and tolerability. We then discuss the role of GH32 substrate specificity in the selective microbial utilization of 1-kestose and related fructooligosaccharides, particularly by bifidobacteria and representative butyrate producers. Next, we review the mechanistic rationale and preclinical evidence for co-administration of 1-kestose and long-chain inulin. Human intervention studies have evaluated 1-kestose across gastrointestinal, metabolic, immune-related, neonatal, oncological, and bowel-habit contexts, with emerging evidence of potential benefits. One healthy-adult trial has also evaluated co-administration with long-chain inulin, although direct comparative trials remain an important future priority. Finally, we propose a research framework that integrates high-purity 1-kestose, GH32-dependent microbial selectivity, and qPCR-based baseline stratification and response monitoring. Prospective, independently replicated trials are needed to establish clinical effectiveness and determine the value of biomarker-guided intervention and combination strategies.

Abstract Background Paraprobiotics, the non-viable microbial cells with health benefits, have gained interest as candidates for preventing food allergies owing to their safety and stability. Heat-killed Lactiplantibacillus plantarum FM8 (FM8) has been reported to induce interleukin (IL)-10 production in dendritic cells in vitro; however, its in vivo efficacy as a standalone intervention remains unexplored. We investigated the preventive effect of heat-killed FM8 in a murine model of ovalbumin (OVA)-induced food allergy. Methods BALB/c mice were assigned to control, OVA-induced allergy, or three FM8 treatment groups receiving FM8 at low (2 × 10⁹ CFU/day), medium (1 × 10¹⁰ CFU/day), or high (5 × 10¹⁰ CFU/day) doses. Food allergy was induced by repeated OVA sensitization and challenge. Allergy symptoms, OVA-specific immunoglobulin E (IgE), and IL-10 levels were measured. Tight junction gene expression, mucin production, gut microbiota composition, and short-chain fatty acids (SCFAs) were also analyzed. Results FM8 supplementation attenuated allergic responses in a dose-dependent manner. Allergy symptom scores were reduced in the High group, and the rectal temperature decline following OVA challenge was ameliorated in both the Med and High groups. The sensitization-induced increase in OVA-specific IgE was also attenuated in these groups. IL-4 expression in Peyer’s patches was reduced, whereas colonic IL-10 expression and serum IL-10 levels were increased in the High group. FM8 supplementation was further associated with increased ileal expression of tight junction-related genes ( Occludin , Claudin-1 and Zo-1 ) and Muc2 , along with a trend toward increased fecal mucin levels; however, no comparable changes in tight junction-related gene expression were observed in the colon. Although taxa with reported SCFA-producing potential were enriched in the High group, cecal acetate and propionate levels remained unchanged, while butyrate levels were decreased. Conclusions FM8 may prevent food allergy by promoting IL-10-associated immunoregulation and enhancing gut barrier-related responses, without a corresponding increase in cecal SCFA concentrations. The contribution of SCFA-related mechanisms remains to be clarified, and further studies are needed to determine clinically feasible dosing and efficacy in humans.

Abstract The gut microbiome is a potential source of non-invasive cancer biomarkers. We evaluated six fecal microbial markers and developed targeted qPCR-based logistic models for colorectal cancer (CRC) and pancreatic cancer (PC). Using LASSO with the 1-standard-error rule, four markers were selected for CRC (afb, nan, fsr, and 5ar) and three for PC (but, fsr, and saa). In post-selection leave-one-out cross-validation of fixed model structures, the CRC and PC models yielded AUCs of 0.824 and 0.780, respectively. Fixed-model application yielded AUCs of 0.716 for colorectal adenoma and 0.540 for the pancreatic high-risk group. In an exploratory Early PC versus high-risk comparison, the fecal qPCR score showed a higher AUC point estimate than CA19-9, while the difference was not statistically significant. Overall, the disease-specific model performance and fixed-model behavior across clinically related groups support further evaluation of model-derived cancer probability scores as exploratory cancer-assessment tools.