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PubMed2025

Host genetics predominates over gut microbiota in serum copper levels in boars.

Copper is an essential trace element in numerous biological processes; maintaining its homeostasis is crucial for pig health and productivity. In this study, we employed a mixed-effects model to investigate the contributions of host genetics, gut microbiota, and their interactions with serum copper levels in pigs. We further explored potential candidate genes and microbiota associated with copper metabolism. The results demonstrated that host genetics exert a dominant influence on serum copper regulation compared to the effects of the gut microbiota. Furthermore, genome-wide association analysis identified 4 candidate genes, CPHL1, CP, NCEH1, and PDE10A, strongly linked to copper metabolism. By applying multiple association approaches, 10 bacterial genera, such as Blautia, Lachnospiraceae UCG-008, and Ruminococcaceae UCG-007 were found to be significantly correlated with serum copper levels. This research offers novel insights into the genetic and microbial determinants of copper variation in pigs, establishing a foundation for future genetic and microbiota-based strategies aimed at enhancing copper homeostasis and overall livestock health.

Animals↗
PubMed2025

Interaction of host gene-gut microbiota in male grading of Macrobrachium rosenbergii.

UNLABELLED: The giant freshwater prawn (GFP; Macrobrachium rosenbergii), a crustacean of high nutritional and economic value, is crucial for aquaculture. During the same growth cycle, male GFPs develop into three distinct forms: small males, orange claw males, and blue claw males. These morphotypes display varying social behaviors, which severely constrain their industrial development. To address this, this study collected male GFP samples at critical developmental time points (100, 110, and 120 days post-hatching) for phenotypic trait measurement and analysis to obtain external morphological data. Through gut microbiota diversity analysis, we identified key gut bacteria (Lactococcus garvieae and Lactobacillus taiwanensis) influencing male morphotype differentiation. Transcriptomic analysis revealed host Kyoto Encyclopedia of Gene and Genome pathways and key genes (Wnt-6, CTSB, CTSL, PPAE, and TP53) associated with morphotype differentiation. The interactions among phenotypic traits, gut microbiota, and key genes were systematically studied through association analysis. Weighted gene co-expression network analysis was employed to construct co-expression modules, from which critical gene modules influencing phenotypic variation were identified. Through association network analysis, we established an "Achromobacter-CD-TRINITY_DN93139_c0_g2 (calpain clp-1)" interaction model. Our findings provide novel insights into the genetic enhancement of GFPs and offer guidelines for future research regarding gut symbiotic bacteria and breeding initiatives. IMPORTANCE: Male Macrobrachium rosenbergii (giant freshwater prawn [GFP]) in the same growth cycle will develop into small males, orange claw males, and blue claw males. This individual heterogeneity in growth significantly impacts the benefits of aquaculture. However, the factors influencing the differentiation of male GFP morphotype remain unclear. This study analyzed the phenotypic data of various GFP levels, the structure of the intestinal microbiota, and the differential genes within the gonadal transcriptome at critical time points of male GFP-level type differentiation. The aim was to explore the potential role of intestinal microbiota and differential genes in this phenomenon. This study offers new insights into the research on the phenomenon of male GFP-level type differentiation.

Animals↗
PubMed2026

Deciphering the Microbiome-Gut-Eye Axis: A Mendelian Randomization Analysis of the Causal Influence of Gut Microbiota on Myopia.

INTRODUCTION: The intricate relationship between the gut microbiome and myopia is increasingly recognized, underscoring the need to explore its causal dynamics. Despite emerging evidence, the influence of Gut Microbiota (GM) on ocular development remains underexplored. METHODS: This study utilized Mendelian Randomization (MR) to investigate the causal impact of GM on the development of myopia. Instrumental variables (IVs) were identified from Genome-Wide Association Studies (GWAS), focusing on genetic variants significantly associated with microbiome composition. A comprehensive array of MR techniques was applied to ensure a robust estimation of causal effects and to adjust for potential confounders and pleiotropy. RESULTS: The Inverse-Variance Weighted (IVW) method was used to identify significant associations between GM and myopia. Increased risk of myopia was linked to the class Betaproteobacteria (OR=1.01, 95% CI 1.004-1.017, P=0.003), the order Burkholderiales (OR=1.009, 95% CI 1.001-1.016, P=0.02), the family Oxalobacteraceae (OR=1.005, 95% CI 1.001-1.01, P=0.023), and several genera including Eubacterium xylanophilum group (OR=1.007, 95% CI 1.001-1.013, P=0.033), and Bifidobacterium (OR=1.005, 95% CI 1-1.01, P=0.038). Protective effects were noted for the order Mollicutes RF9 (OR=0.994, 95% CI 0.99-0.999, P=0.014), the genus Allisonella (OR=0.996, 95% CI 0.993-0.999, P=0.019), the genus Lachnospiraceae UCG001 (OR=0.994, 95% CI 0.989-1, P=0.045), and the family Enterobacteraceae (OR=0.991, 95% CI 0.982-1, P=0.047) and order Enterobacteriales (OR=0.991, 95% CI 0.982-1, P=0.047). Sensitivity analyses further confirmed the robustness of these findings. DISCUSSION: This study provides causal evidence for the "Microbiome-Gut-Eye Axis" in myopia development, identifying specific gut microbiota that influence myopia risk. These findings suggest potential for microbiota-targeted interventions, warranting further research in diverse populations. CONCLUSIONS: The findings support the "Microbiome-Gut-Eye Axis" as a potential factor in myopia pathogenesis and highlight microbiota-targeted interventions as novel therapeutic strategies for managing myopia. This study lays the groundwork for further research on how modifying GM can influence eye health and offers new perspectives on preventive health strategies.

Humans↗
PubMed2026

Comprehensive In Vitro, Genomic, Microbiota, and Subacute Toxicological Safety Characterization of Lactiplantibacillus plantarum ATA-LPC98052.

BACKGROUND: Lactiplantibacillus plantarum is a widely studied probiotic species; however, probiotic characteristics and safety profiles are strain-specific, requiring independent evaluation. This study characterized Lactiplantibacillus plantarum ATA-LPC98052 as a candidate probiotic raw material. METHODS: ATA-LPC98052 was evaluated for hemolysis, acid/bile tolerance, Caco-2 adhesion, cytotoxicity, and storage stability. Subacute oral safety was assessed in Wistar rats by gavage for 28 days at 1.2 × 1011 CFU/kg/day; the study design incorporated selected principles of OECD Test Guideline 407. Clinical, hematological, biochemical, organ-weight, and macroscopic endpoints were evaluated. Fecal microbiota was analyzed by 16S rRNA sequencing; WGS was used for taxonomic confirmation and genomic safety screening. RESULTS: ATA-LPC98052 was γ-hemolytic and maintained 60% viability at pH 1.5 and 96% at pH 5.0, while viability ranged from 74% to 82% across 0.1-0.5% bile salt concentrations. Caco-2 cell viability was 99%, adhesion exceeded 90%, and the lyophilized preparation remained stable for 15 months, maintaining 9.6 log10 CFU/g. Repeated oral administration caused no mortality or consistent treatment-related toxicological pattern. Longitudinal microbiota analysis showed no significant treatment × time effects on alpha diversity or Bray-Curtis community structure, and no genus-level MaAsLin2 association was FDR-significant. WGS confirmed L. plantarum identity and no contamination; ResFinder detected no acquired antimicrobial resistance determinants meeting specified thresholds, whereas CARD/RGI identified low-identity qacJ and vanY homologs requiring cautious interpretation. CONCLUSION: ATA-LPC98052 demonstrated favorable in vitro probiotic characteristics, technological stability, gut microbiota-modulating potential, and a favorable subacute safety profile under the tested conditions; however, microbiota findings were exploratory, and phenotypic MIC testing remains warranted.

Animals↗
PubMed2007

Intestinal microbiota: a potential diet-responsive prevention target in ApcMin mice.

We previously reported that two dietary regimens, calorie restriction (CR) and a high olive oil-containing diet supplemented with a freeze-dried fruit and vegetable extract (OFV), reduced the development of intestinal adenomas in Apc(Min) mice by 57% and 33%, respectively, compared to control mice fed a defined diet ad libitum. The OFV diet was designed to have a strong effect on the composition of the intestinal microbiota through its high content of fiber, which represents a major source of fermentable substrate for the gut bacteria. We hypothesized that some of the observed effects of diet on intestinal carcinogenesis might be mediated by diet-related changes in the bacterial species that thrive in the gut. Therefore, we determined by fluorescent in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE) how the dietary interventions affected the composition of the intestinal microbiota, and we characterized specific microbiota changes that were associated with diet and reduced intestinal carcinogenesis. The OFV diet changed the overall composition of the intestinal microbiota, smaller changes were observed for the CR diet. Furthermore, we detected a 16S rDNA fragment associated with mice that did not develop polyps. Sequence analysis suggested that hitherto unidentified bacteria belonging to the family Lachnospiraceae (order Clostridiales) were its source. Thus, these bacteria may be an indicator of intestinal conditions associated with reduced intestinal carcinogenesis in Apc(Min) mice.

Adenoma↗
PubMed2006

Genetic and physiological characterization of the intestinal bacterial microbiota of Bluegill (Lepomis macrochirus) with three different feeding habits.

Bluegill (Lepomis macrochirus) in Lake Biwa, Japan, feed on benthic invertebrates (benthivorous type), aquatic plants (herbivorous type), and zooplankton (planktivorous type). To evaluate the effect of food on intestinal bacterial microbiota, we characterized and compared the intestinal microbiota of these three types of bluegill in terms of community-level physiological profile (CLPP) and genetic structure. The CLPP was analyzed using Biolog MicroPlates (Biolog, Inc., Hayward, CA, USA), and multivariate analysis of variance revealed that the CLPP of intestinal microbiota differed significantly between any pairs of the three types of bluegill. The genetic profiles were analyzed by temperature gradient gel electrophoresis of polymerase chain reaction (PCR)-amplified 16S rDNA fragments, and multidimensional scaling indicated the existence of specific intestinal bacterial structures for both the benthivorous and the planktivorous types. These results suggest that the host's feeding habit can be one factor controlling the intestinal microbiota of fish in the natural environment.

Animals↗
PubMed2005

Comparison of cellular fatty acid profiles of the microbiota in different gut regions of BALB/c and C57BL/6J mice.

The gastrointestinal tracts of developed animals are colonized by an extremely complex and diverse microbial ecosystem. The host and its microbiota are in close interaction with each other, and the host's genetic characteristics have been suggested to have an influence on the composition of fecal bacteria. However, different sections of gastrointestinal tract harbor microbes typical of each particular section and knowledge of the effect of the host's genotype on the microbiota in the different parts of the gastrointestinal tract is limited. In this study, mice from two inbred strains, C57BL/6J and BALB/c, were raised in identical conditions. Bacterial samples were collected from four parts of the gastrointestinal tract and analyzed for bacterial fatty acids using gas-liquid chromatography (GLC). Significant differences between the microbiota in the feces, in the cecum, in the small bowel and in the stomach were observed. Cecal samples produced more diverse bacterial fatty acid profiles than any of the other samples, revealing a higher bacterial density and a higher number of bacterial species. Further, a significant difference between the two strains of mice was observed throughout the gastrointestinal tract. These findings indicate that the host's genotype has an influence on the gastrointestinal microbiota as a whole, and provide further evidence that the cecum is the most species-rich region of the murine gut.

Animals↗
PubMed2026

Comparative analysis of gut microbiota in yaks under different feeding management strategies during cold seasons.

Yaks (Bos grunniens) are crucial for the livelihoods of pastoral communities in cold regions, where feed scarcity during the cold season poses challenges to their health and productivity, underscoring the necessity of understanding how dietary management influences the gut microbiota. In this study, 24 yak steers matched for body weight and health status were randomly allocated to four groups: natural grazing or indoor feeding with roughage-to-concentrate ratios of 50:50, 70:30, or 90:10. Fecal samples were collected for 16S rDNA sequencing and subsequent functional prediction of the microbiota. The results showed that Firmicutes and Bacteroidetes were the dominant phyla across all groups, and UCG-005 and Rikenellaceae_RC9_gut_group were the predominant genera. Concentrate supplementation during the cold season significantly enhanced microbial richness and diversity, with the 70:30 ratio exerting the most pronounced beneficial effects on microbiota structure and key taxa enrichment. These findings highlight the critical role of dietary management in shaping the yak gut microbiota during cold seasons and suggest that the 70:30 ratio optimally improves microbial community structure, thereby promoting yak health and productivity under harsh climatic conditions. Future research should explore the long-term implications of such dietary strategies.

Animals↗
PubMed2005

Molecular monitoring and characterization of the faecal microbiota of healthy dogs during fructan supplementation.

The large intestine of dogs contains a complex microbial ecosystem with predominance of streptococci, bifidobacteria, lactobacilli, Bacteroides and Clostridium. Generally, this predominant microbiota in dogs is relatively stable in time but much less is known about its taxonomic composition. Moreover, almost no studies have been conducted to investigate this stability of the faecal microbial population in dogs upon prebiotic administration. The objective of the present study was to monitor possible changes in faecal microbiota of seven healthy adult dogs related to the administration of two fructans, oligofructose and inulin. For this purpose, population fingerprints generated by denaturing gradient gel electrophoresis (DGGE) analysis of universal V3 16 S rRNA gene PCR amplicons were compared between control (baseline) samples and samples collected after prebiotic feeding. From these DGGE gels, marked changes were observed in the faecal microbiota between subjects and before and after fructan administration. One DGGE band that appeared or intensified after fructan intake was further analyzed. Sequence analysis could attribute this band to a member of the Streptococcus bovis-equinus group. Following cultivation on MRS medium, a set of faecal isolates that most likely represent the stimulated streptococci were allocated to the species Streptococcus lutetiensis by (GTG)(5)-PCR fingerprinting and partial 16 S rRNA and sodA gene sequencing. The data provided in this study demonstrate the ability of fructans to influence the bacterial composition of the gut microbiota in healthy dogs. More work is needed to unravel the relevance of S. lutetiensis or other autochthonous organisms of the dog gut as target groups for prebiotic supplementation.

Animals↗
PubMed2004

Indigenous raw milk microbiota influences the bacterial development in traditional cheese from an alpine natural park.

Nostrano di Primiero is a 6-month ripened cheese produced from raw milk collected in the Paneveggio-Pale di San Martino Natural Park area in the Italian Dolomites. In summer, this cheese is made using milk collected from two different areas, Passo Rolle and Vanoi, in the Paneveggio Natural Park. During the experiment, the milk from the two areas was separately processed, and cheeses were made in the same cheese factory using the same technological process. The microbiota of raw milk and cheeses of the two areas was isolated and the dominant population was monitored by RAPD analysis and identified by 16S rRNA sequence. The milk of the Passo Rolle area was mainly composed of mesophilic strains, thermophilic Streptococcus thermophilus, and low amounts of enterococci were also found; the milk of the Vanoi area was dominated by mesophilic microbiota mostly Lactococcus lactis ssp. cremoris and ssp. lactis and Lactobacillus paracasei ssp. paracasei. The plating of the natural starter culture revealed the presence of a relevant community of thermophilic cocci and lower amounts of enterococci. The dynamic population analysis showed the importance of the natural starter culture in the first 2 days of cheese ripening in both cheeses. Moreover, the large biodiversity observed in the raw milks was also detected in the cheeses during ripening. The Vanoi cheese was dominated by Enterococcus faecium and Streptococcus macedonicus in the first two days and mesophilic 21 Lb. paracasei ssp. paracasei became the most represented population after 15 days of ripening. In the first few days, the Rolle cheese was characterized by being mainly composed of thermophilic S. macedonicus and S. thermophilus and secondarily by mesophilic cocci. During ripening, the microbiota composition changed, and at 15 days, mesophilic lactobacilli were the dominant population, but later, this was mainly composed of mesophilic cocci and lactobacilli. The taxonomical identification by 16S rRNA sequence confirmed a large biodiversity related to raw milk microbiota and only five strains of S. macedonicus, Lactobacillus plantarum, 21 Lb. paracasei ssp. paracasei, Lactobacillus fermentum and E. faecium were detected in both cheeses.

Animals↗
PubMed2006

Potential role for gut microbiota in cell wall digestion and glucoside detoxification in Tenebrio molitor larvae.

Tenebrio molitor larvae were successfully reared free of cultivatable gut lumen bacteria, yeasts and fungi using two approaches; aseptic rearing from surface sterilized eggs and by feeding larvae with antibiotic-containing food. Insects were reared on a rich-nutrient complete diet or a nutrient-poor refractory diet. A comparison of digestive enzyme activities in germ free and conventional insects containing a gut microbiota did not reveal gross differences in enzymes that degrade cell walls from bacteria (lysozyme), fungi (chitinase and laminarinase) and plants (cellulase and licheninase). This suggested that microbial-derived enzymes are not an essential component of the digestive process in this insect. However, more detailed analysis of T. molitor midgut proteins using an electrophoretic separation approach showed that some digestive enzymes were absent and others were newly expressed in microbiota-free larvae. Larvae reared in antibiotic-containing refractory wheat bran diet performed poorly in comparison with controls. The addition of saligenin, the aglycone of the plant glucoside salicin, has more deleterious effects on microbiota-free larvae than on the conventionally reared larvae, suggesting a detoxifying role of midgut microbiota. Analysis of the volatile organic compounds released from the faecal pellets of the larvae shows key differences in the profiles from conventionally reared and aseptically reared larvae. Pentadecene is a semiochemical commonly found in other beetle species. Here we demonstrate the absence of pentadecene from aseptically reared larvae in contrast to its presence in conventionally reared larvae. The results are discussed in the light of the hypothesis that microbial products play subtle roles in the life of the insect, they are involved in the digestion of refractory food, detoxification of secondary plant compounds and modify the volatile profiles of the insect host.

Animals↗
PubMed2005

Comparison of methods and animal models commonly used for investigation of fecal microbiota: effects of time, host and gender.

Denaturing gradient gel electrophoresis (DGGE), terminal restriction fragment length polymorphism (T-RFLP) and plating on selective agars were used to study variation in the fecal microbiota of rats over time as well as variation between individuals. Investigated rats were either conventional and specific pathogen free (SPF), or human flora associated (HFA). A higher variation (p<0.05) in fecal microbiota over time was observed for HFA than for SPF animals. Analysis of DGGE and T-RFLP profiles of fecal microbiota from SPF and HFA rats revealed that variation over time was less significant than variation between individuals, and that phylogenetic profiles clustered according to gender. These observations should be taken into account when designing future research addressing changes in fecal microbiota.

Adult↗
PubMed2004

Association of T CD4 lymphocyte levels and subgingival microbiota of chronic periodontitis in HIV-infected Brazilians under HAART.

OBJECTIVE: The aim of this study was to determine the subgingival microbiota of HIV-infected patients with chronic periodontitis and different T CD4 lymphocyte levels under HAART. STUDY DESIGN: 64 HIV+ patients (mean age 34.5 +/- 7.3; 75% males) were distributed into Group I: chronic periodontitis (> or = 3 sites with probing pocket depth (PPD) and/or clinical attachment level (CAL) > or = 5 mm); and Group II: periodontal health (no sites with PPD > 3 mm and/or CAL > 4 mm). All subjects received conventional periodontal therapy. Periodontal clinical parameters were evaluated at 6 sites/tooth in all teeth at baseline and 4 months after therapy. The levels of T CD4 were obtained from the patient's medical record. Subgingival plaque samples were taken from the 6 sites with the largest pocket depth in each subject of Group I, and 6 randomly selected sites in subjects of Group II. The presence of 22 subgingival species was determined using the checkerboard DNA-DNA hybridization method. Significant microbiological differences within and among groups were sought using Wilcoxon signed-rank and Mann-Whitney tests, respectively. Relationships between T CD4 levels and microbiological parameters were determined using Kruskal-Wallis test. RESULTS: Sixty-one percent of the HIV-infected patients represented AIDS cases, although 69% of them were periodontally healthy. The T CD4 lymphocyte mean level was 333 cells/mm3 and viral load was 12,815 +/- 24,607 copies/mm3. Yet, the prevalence of chronic periodontitis was relatively low (36%). Several periodontal pathogens, in particular T. forsythensis (P < .05), were more prevalent in HIV-positive patients with periodontitis than in HIV-positive subjects with periodontal health. Most of the species decreased in frequency after therapy, particularly P. gingivalis (P < .05). E. faecalis and F. nucleatum were significantly more prevalent in the subgingival microbiota of patients with chronic periodontitis and lower levels of T CD4 (P < .05), while beneficial species tended to be more frequently detected in individuals with T CD4 counts over 500 cells/mm3. CONCLUSION: The subgingival microbiota of HIV-infected patients with chronic periodontitis include a high prevalence of classical periodontal pathogens observed in non-infected individuals. Furthermore, the severe immunosuppression seems to favor the colonization by these species, as well as by species not commonly found in the subgingival microbiota.

Adult↗
PubMed2003

Use of denaturing gradient gel electrophoresis for analysis of the stool microbiota of hospitalized patients.

Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified ribosomal RNA gene amplicons was used to study the stool microbiota of hospitalized patients and to examine the effect of antibiotic therapy. For one patient, 16 anaerobic species identified by random cloning and sequencing of PCR-amplified rRNA genes from stool were represented by bands on the DGGE gel. DGGE analysis and similarity index comparisons demonstrated that the anaerobic microbiota of this individual remained stable in the absence of antibiotic therapy, was minimally affected by ciprofloxacin but markedly reduced by clindamycin therapy, and recovery of some organisms was evident within days after discontinuation of clindamycin. DGGE analysis of additional patients demonstrated similar disruptions of the intestinal microbiota associated with antibiotic therapy. The DGGE banding patterns of nine patients showed considerable variability, but several bands were shared among patients. Thus, our findings are consistent with previous studies that utilized culture techniques, and suggest that DGGE is a useful technique for analysis of the stool microbiota of hospitalized patients.

Actinobacteria↗
PubMed2006

Metabolic profiling reveals a contribution of gut microbiota to fatty liver phenotype in insulin-resistant mice.

Here, we study the intricate relationship between gut microbiota and host cometabolic phenotypes associated with dietary-induced impaired glucose homeostasis and nonalcoholic fatty liver disease (NAFLD) in a mouse strain (129S6) known to be susceptible to these disease traits, using plasma and urine metabotyping, achieved by (1)H NMR spectroscopy. Multivariate statistical modeling of the spectra shows that the genetic predisposition of the 129S6 mouse to impaired glucose homeostasis and NAFLD is associated with disruptions of choline metabolism, i.e., low circulating levels of plasma phosphatidylcholine and high urinary excretion of methylamines (dimethylamine, trimethylamine, and trimethylamine-N-oxide), coprocessed by symbiotic gut microbiota and mammalian enzyme systems. Conversion of choline into methylamines by microbiota in strain 129S6 on a high-fat diet reduces the bioavailability of choline and mimics the effect of choline-deficient diets, causing NAFLD. These data also indicate that gut microbiota may play an active role in the development of insulin resistance.

Animals↗
PubMed2005

Evidence of vancomycin resistance gene transfer between enterococci of human origin in the gut of mice harbouring human microbiota.

OBJECTIVES: Potential intra- and inter-species transfers of vancomycin resistance genes (vanA gene cluster) between Enterococcus strains were evaluated in the gut of heteroxenic mice harbouring a human microbiota. METHODS: Mice colonized with a stable population of E. faecium 64/3 or E. faecalis JH2-2 recipient strain and harbouring an enterococci-free human microbiota were obtained. Donor strain E. faecium HC-VI2 of clinical origin was administered orogastrically to these mice and transfers were evaluated over time in faecal samples. RESULTS: Only intraspecies transfers were detected in the digestive tract (DT) of mice harbouring a human microbiota. E. faecium 64/3 transconjugants were detected at several sampling times over the 60 day experiment to levels up to 10(3) cfu/g of faeces, but they did not steadily colonize the DT. CONCLUSIONS: Here, we show for the first time that transfer of the vanA gene cluster can occur between Enterococcus strains in the DT colonized with a human microbiota and in the absence of selective pressure. The colonization properties of other enterococci transconjugants and the influence of vancomycin intake should be further investigated since transfers in the DT of animals and humans might contribute to emergence and dissemination of new vancomycin-resistant bacteria.

Animals↗
PubMed1995

Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics.

Because the human gut microbiota can play a major role in host health, there is currently some interest in the manipulation of the composition of the gut flora towards a potentially more remedial community. Attempts have been made to increase bacterial groups such as Bifidobacterium and Lactobacillus that are perceived as exerting health-promoting properties. Probiotics, defined as microbial food supplements that beneficially affect the host by improving its intestinal microbial balance, have been used to change the composition of colonic microbiota. However, such changes may be transient, and the implantation of exogenous bacteria therefore becomes limited. In contrast, prebiotics are nondigestible food ingredients that beneficially affect the host by selectively stimulating the growth and/or activity of one or a limited number of bacterial species already resident in the colon, and thus attempt to improve host health. Intake of prebiotics can significantly modulate the colonic microbiota by increasing the number of specific bacteria and thus changing the composition of the microbiota. Nondigestible oligosaccharides in general, and fructooligosaccharides in particular, are prebiotics. They have been shown to stimulate the growth of endogenous bifidobacteria, which, after a short feeding period, become predominant in human feces. Moreover, these prebiotics modulate lipid metabolism, most likely via fermentation products. By combining the rationale of pro- and prebiotics, the concept of synbiotics is proposed to characterize some colonic foods with interesting nutritional properties that make these compounds candidates for classification as health-enhancing functional food ingredients.

Bacteria↗
PubMed2005

Fructooligosaccharides and fiber partially prevent the alterations in fecal microbiota and short-chain fatty acid concentrations caused by standard enteral formula in healthy humans.

The intestinal microbiota are important during enteral tube feeding because they exert colonization resistance and produce SCFAs. However, the effect of the enteral formula composition on major bacterial groups of the microbiota has not been clearly defined. The aim of this study was to investigate the effect of enteral formulas with and without prebiotic fructooligosaccharides (FOS) and fiber on the fecal microbiota and SCFAs. Healthy subjects (n = 10; 4 men, 6 women) consumed both a standard enteral formula and one containing FOS (5.1 g/L) and fiber (8.9 g/L) as a sole source of nutrition for 14 d in a randomized, double-blind, crossover trial with a 6-wk washout phase. Fecal samples were collected at the start and end of each formula phase, and were analyzed for major bacterial groups and SCFA concentrations using fluorescent in situ hybridization and GLC, respectively. Although there were reductions in total fecal bacteria due to both formula treatments, concentrations were higher after the FOS/fiber formula period compared with the standard formula period (11.2 +/- 0.2 vs. 11.0 +/- 0.2 log(10) cells/g, P = 0.005). The FOS/fiber formula increased bifidobacteria (P = 0.004) and reduced clostridia (P = 0.006). Compared with the standard formula, the FOS/fiber formula resulted in higher concentrations of total SCFA (332.4 +/- 133.8 vs. 220.1 +/- 124.5 micromol/g, P = 0.022), acetate (219.6 +/- 96.3 vs. 136.8 +/- 74.5 micromol/g, P = 0.034) and propionate (58.4 +/- 37.4 vs. 35.6 +/- 25.5 micromol/g, P = 0.02). This study demonstrates that standard enteral formula leads to adverse alterations to the fecal microbiota and SCFA concentrations in healthy subjects, and these alterations are partially prevented by fortification of the formula with FOS and fiber.

Bacteria↗