Probiotics are live microorganisms exerting beneficial effects on the host\'s health when administered in adequate amounts. Among the most popular and adequately studied probiotics are bacteria from the families Lactobacillaceae, Bifidobacteriaceae and yeasts. Most of them have been shown, both in vitro and in vivo studies of intestinal inflammation models, to provide favorable results by means of improving the gut microbiota composition, promoting the wound healing process and shaping the immunological responses. Chronic intestinal conditions, such as inflammatory bowel diseases (IBD), are characterized by an imbalance in microbiota composition, with decreased diversity, and by relapsing and persisting inflammation, which may lead to mucosal damage. Although the results of the clinical studies investigating the effect of probiotics on patients with IBD are still controversial, it is without doubt that these microorganisms and their metabolites, now named postbiotics, have a positive influence on both the host\'s microbiota and the immune system, and ultimately alter the topical tissue microenvironment. This influence is achieved through three axes: (1) By displacement of potential pathogens via competitive exclusion; (2) by offering protection to the host through the secretion of various defensive mediators; and (3) by supplying the host with essential nutrients. We will analyze and discuss almost all the in vitro and in vivo studies of the past 2 years dealing with the possible favorable effects of certain probiotic genus on gut immunological responses, highlighting which species are the most beneficial against intestinal inflammation.

The human gut microbiota is characterized by large interpersonal differences, which are not only linked to health and disease but also determine the outcome of nutritional interventions. In line with the growing interest for developing targeted gut microbiota modulators, the selectivity of a carrot-derived rhamnogalacturonan I (cRG-I) was compared to substrates with demonstrated low (inulin, IN) and high selectivity (xanthan, XA), at a human equivalent dose (HED) of 1.5 g/d. The high throughput of the ex vivo SIFR® technology, validated to generate predictive insights for clinical findings, enabled the inclusion of 24 human adults. Such an unprecedented high number of samples in the context of in vitro gut microbiota modelling allowed a coverage of clinically relevant interpersonal differences in gut microbiota composition and function. A key finding was that cRG-I supplementation (already at an HED of 0.3 g/d) lowered interpersonal compositional differences due to the selective stimulation of taxa that were consistently present among human adults, including OTUs related to Bacteroides dorei/vulgatus and Bifidobacterium longum (suspected keystone species), Bacteroides thetaiotaomicron, Bifidobacterium adolescentis and butyrate-producing taxa such as Blautia sp., Anaerobutyricum hallii, and Faecalibacterium prausnitzii. In contrast, both IN and XA treatments increased interpersonal compositional differences. For IN, this followed from its low specificity. For XA, it was rather the extremely high selectivity of XA fermentation that caused large differences between 15 responders and 9 nonresponders, caused by the presence/absence of highly specific XA-fermenting taxa. While all test compounds significantly enhanced acetate, propionate, butyrate, and gas production, cRG-I resulted in a significantly higher acetate (+40%), propionate (+22%), yet a lower gas production (-44%) compared to IN. cRG-I could thus result in overall more robust beneficial effects, while also being better tolerated. Moreover, owing to its remarkable homogenization effect on microbial composition and metabolite production, cRG-I could lead to more predictable outcomes compared to substrates that are less specific or overly specific.

Research on the role of gut microbiota in behavior has grown dramatically. The probiotic L. reuteri can alter social and stress-related behaviors - yet, the underlying mechanisms remain largely unknown. Although traditional laboratory rodents provide a foundation for examining the role of L. reuteri on the gut-brain axis, they do not naturally display a wide variety of social behaviors. Using the highly-social, monogamous prairie vole (Microtus ochrogaster), we examined the effects of L. reuteri administration on behaviors, neurochemical marker expression, and gut-microbiome composition. Females, but not males, treated with live L. reuteri displayed lower levels of social affiliation compared to those treated with heat-killed L. reuteri. Overall, females displayed a lower level of anxiety-like behaviors than males. Live L. reuteri-treated females had lower expression of corticotrophin releasing factor (CRF) and CRF type-2-receptor in the nucleus accumbens, and lower vasopressin 1a-receptor in the paraventricular nucleus of the hypothalamus (PVN), but increased CRF in the PVN. There were both baseline sex differences and sex-by-treatment differences in gut microbiome composition. Live L. reuteri increased the abundance of several taxa, including Enterobacteriaceae, Lachnospiraceae NK4A136, and Treponema. Interestingly, heat-killed L. reuteri increased abundance of the beneficial taxa Bifidobacteriaceae and Blautia. There were significant correlations between changes in microbiota, brain neurochemical markers, and behaviors. Our data indicate that L. reuteri impacts gut microbiota, gut-brain axis and behaviors in a sex-specific manner in socially-monogamous prairie voles. This demonstrates the utility of the prairie vole model for further examining causal impacts of microbiome on brain and behavior.

Current therapeutic strategies for Clostridioides difficile infections (CDI), including oral vancomycin, metronidazole and fecal microbial transplantation, have limited efficacy and treatment failure may occur in as many as one- third of cases. Recent studies have reported that lower concentrations of 25-hydroxyvitamin D are associated with CDI severity and recurrence. However, there have been no studies on microbiota composition after the administration of vitamin D in patients with CDI. Therefore, our study aimed to compare the microbiota composition between the two groups, including eight CDI-positive patients with vitamin D supplementation and ten CDI-positive patients without vitamin D supplementation by using 16S rRNA microbial profiling.
Twenty subjects were enrolled in this prospective randomized controlled study. One subject dropped out due to lack of contact with the guardian after discharge and one subject dropped out due to withdrawal of consent. Thus, 18 patients with CDI and vitamin D insufficiency (vitamin D level < 17 ng/mL) were divided into two groups: CDI with vitamin D supplementation (n = 8) and CDI without vitamin D supplementation (control: n = 10). Subjects with vitamin D insufficiency were randomized to receive 200,000 IU intramuscular cholecalciferol whereas patients in the control group received only oral vancomycin. Stool samples were obtained twice before vancomycin was administered and eight weeks after treatment; the V3-V4 16S rRNA metagenomic sequencing was performed using EzBioCloud.
The alpha diversity of the gut microbiota in the recovery state was significantly higher than that in the CDI state. Analysis of bacterial relative abundance showed significantly lower Proteobacteria and higher Lachnospiraceae, Ruminococcaceae, Akkermansiaceae, and Bifidobacteriaceae in the recovery state. When comparing the control and vitamin D treatment groups after eight weeks, increase in alpha diversity and, abundance of Lachnospiraceae, and Ruminococcaceae exhibited the same trend in both groups. A significant increase in Bifidobacteriaceae and Christensenellaceae was observed in the vitamin D group; Proteobacteria abundance was significantly lower in the vitamin D treatment group after eight weeks than that in the control group.
Our study confirmed that the increase in the abundance of beneficial bacteria such as Bifidobacteriaceae, and Christensenellaceae were prominently evident during recovery after administration of a high dose of cholecalciferol. These findings indicate that vitamin D administration may be useful in patients with CDI, and further studies with larger sample sizes are required.

Stingless bees (Apidae: Meliponini) are the most diverse group of corbiculate bees and are important managed and wild pollinators distributed in the tropical and subtropical regions of the globe. However, little is known about their associated beneficial microbes that play major roles in host nutrition, detoxification, growth, activation of immune responses, and protection against pathogens in their sister groups, honeybees and bumble bees. Here, we provide an initial characterization of the gut bacterial microbiota of eight stingless bee species from sub-Saharan Africa using 16S rRNA amplicon sequencing. Our findings revealed that Firmicutes, Actinobacteria, and Proteobacteria were the dominant and conserved phyla across the eight stingless bee species. Additionally, we found significant geographical and host intra-species-specific bacterial diversity. Notably, African strains showed significant phylogenetic clustering when compared with strains from other continents, and each stingless bee species has its own microbial composition with its own dominant bacterial genus. Our results suggest host selective mechanisms maintain distinct gut communities among sympatric species and thus constitute an important resource for future studies on bee health management and host-microbe co-evolution and adaptation.

Bifidobacteriaceae family are gut microbiota that exhibit probiotic or health promoting effects on the host. Several studies have suggested that gut microbiota are quantitatively and qualitatively altered in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). The present study aimed to assess the members of Bifidobacteriaceae family in fecal samples of patients with CKD and ESRD and compare them with non-CKD/ESRD patients to find any changes in their counts and diversions in these patients. Twenty fresh fecal samples from patients with CKD/ESRD and twenty from non-CKD/ESRD patients were examined. Whole DNA was extracted from fecal samples and the gut microbiota composition was analyzed by next generation sequencing (NGS). A total of 651 strains were identified from 40 fecal samples, 8 (1.23%) strains of which were identified as family Bifidobacteriaceae. The most abundant species in both control and disease groups were Bifidobacterium adolescentis and Bifidobacterium longum subsp. longum, and the least abundant species in the disease group was Bifidobacterium animalis subsp. lactis. There was no significant difference in the abundance of various species between the disease and control groups (p < 0.05). This study confirms that the members of the Bifidobacteriaceae family are not altered in patients with CKD/ESRD.

The human gut microbiome is currently recognized to play a vital role in human biology and development, with diet as a major modulator. Therefore, novel indigestible polysaccharides that confer a health benefit upon their fermentation by the microbiome are under investigation. Based on the recently demonstrated prebiotic potential of a carrot-derived pectin extract enriched for rhamnogalacturonan I (cRG-I), the current study aimed to assess the impact of cRG-I upon repeated administration using the M-SHIME technology (3 weeks at 3g cRG-I/d). Consistent effects across four simulated adult donors included enhanced levels of acetate (+21.1 mM), propionate (+17.6 mM), and to a lesser extent butyrate (+4.1 mM), coinciding with a marked increase of OTUs related to Bacteroides dorei and Prevotella species with versatile enzymatic potential likely allowing them to serve as primary degraders of cRG-I. These Bacteroidetes members are able to produce succinate, explaining the consistent increase of an OTU related to the succinate-converting Phascolarctobacterium faecium (+0.47 log10(cells/mL)). While the Bifidobacteriaceae family remained unaffected, a specific OTU related to Bifidobacterium longum increased significantly upon cRG-I treatment (+1.32 log10(cells/mL)). Additional monoculture experiments suggested that Bifidobacterium species are unable to ferment cRG-I structures as such and that B. longum probably feeds on arabinan and galactan side chains of cRG-I, released by aforementioned Bacteroidetes members. Overall, this study confirms the prebiotic potential of cRG-I and additionally highlights the marked consistency of the microbial changes observed across simulated subjects, suggesting the involvement of a specialized consortium in cRG-I fermentation by the human gut microbiome.

Numerous studies have examined the link between the presence of specific gastrointestinal bacteria and the feed efficiency of cattle. However, cattle undergo dietary changes during their productive life which can cause fluctuations in their microbial consortium. The objective of the present study was to assess changes in the fecal microbiome of beef steers genetically selected to be divergent in feedlot feed efficiency, to determine whether differences in their fecal microbiomes could be detected as early as weaning, and continued throughout the rearing process regardless of dietary changes. Fecal samples were collected at weaning, yearling age, and slaughter for a group of 63 steers. Based on their feedlot-finishing performance, the steers were selected and divided into two groups according to their residual feed intake (RFI): efficient steers (low-RFI; n = 7) and inefficient steers (high-RFI; n = 8). To ascertain the fecal microbial consortium and volatile fatty acid (VFA) content, 16S rRNA gene sequencing and VFA analysis were performed. Overall, bacterial evenness and diversity were greater at weaning compared to yearling and slaughter for both efficiency groups (P < 0.001). Feedlot RFI linearly decreased as both Shannon diversity and Ruminococcaceae abundance increased (R 2 = 65.6 and 60.7%, respectively). Abundances of Ruminococcaceae, Rikenellaceae, and Christensenellaceae were higher at weaning vs. yearling age and slaughter (P < 0.001); moreover, these families were consistently more abundant in the feces of the low-RFI steers (for most of the timepoints evaluated; P ≤ 0.05), compared to the high-RFI steers. Conversely, abundances of Bifidobacteriaceae were numerically higher in the feces of the high-RFI steers throughout their lifespan. Total VFA concentrations increased at slaughter compared to weaning and yearling for both efficiency groups (P < 0.001). The acetate:propionate ratio decreased linearly (P < 0.001) throughout the life of the steers regardless of their efficiency, reflective of dietary changes. Our results indicate that despite fluctuations due to animal age and dietary changes, specific bacterial families may be correlated with feed efficiency of steers. Furthermore, such differences may be identifiable at earlier stages of the production cycle, potentially as early as weaning.

OBJECTIVE: The aims of this study are as follows: (1) to understand the relationship between gut microbiota and the choking phenomenon in diving athletes, and (2) to regulate the gut microbiota in diving athletes by drinking yogurt containing Bifidobacterium animalis subsp. lactis BB-12 and observe changes in the choking phenomenon in diving athletes.
METHODS: Experiment 1: A total of 20 diving athletes were tested in low- and high-pressure situations. Gut microbiota (n = 18) composition was then determined and differences in the gut microbiota composition among diving athletes who presented choking vs. no choking were identified. Experiment 2: A total of 16 divers who presented choking were divided into a high yogurt group (n = 6) and a low yogurt group (n = 10) for 15 days.
RESULTS: (1) The content of Veillonellaceae in divers who presented choking was significantly higher when compared to divers who did not present choking (p < 0.05). Bifidobacteriaceae (r = -0.52, p < 0.05) and Lactobacillaceae (r = -0.66, p < 0.05) were negatively correlated with the choking index. (2) During experiment 2, the average daily intake of the high yogurt group was 611.78 ± 94.94 mL and the average daily intake of the low yogurt group was 338 ± 71.45 mL and the abundance of Bifidobacteriaceae was significantly higher in the high yogurt group than in the low yogurt group. After the experiment, the choking index in the high yogurt group became significantly lower than that of the low yogurt group (z = -3.26, p < 0.001).
CONCLUSIONS: The intake of yogurt containing B. animalis subsp. lactis can increase the abundance of Bifidobacteriaceae in elite diving athletes and their performance under high pressure. Hence, gut microbiota may affect the choking phenomenon in elite diving athletes.

The objective of this study was to evaluate the effect of yellow mealworm (Tenebrio molitor L.) exuviae (ME) given as a prebiotic in 20% of the diet fed to BALB/c mice. Analysis of the ME revealed that it was mostly composed of crude protein (52.94%), crude fiber (10.70%), and moisture (10.54%). When ME was fed to mice for 8 weeks, the number of intestinal lactic acid bacteria increased, reaching similar numbers (4.50 ± 0.80 CFU/mL) to those (4.70 ± 0.80 CFU/mL) of the control group not fed ME. Microbiome analysis showed that 8 weeks feeding of ME promoted the growth of Bifidobacteriaceae and Lactobacillaceae compared to the POS group, indicating the positive effects of feeding 20% ME on the intestinal microbiota of mice. These results suggest that ME can be considered as a dietary prebiotics to improve human gut microbial population, but further application study to human is necessary.