Gut Microbiome In Rats Research Articles

Effect of Hesperidin on Chronic Unpredictable Mild Stress-Related Depression in Rats through Gut-Brain Axis Pathway.

To determine the pharmacological impact of hesperidin, the main component of Citri Reticulatae Pericarpium, on depressive behavior and elucidate the mechanism by which hesperidin treats depression, focusing on the gut-brain axis. Fifty-four Sprague Dawley male rats were randomly allocated to 6 groups using a random number table, including control, model, hesperidin, probiotics, fluoxetine, and Citri Reticulatae Pericarpium groups. Except for the control group, rats in the remaining 5 groups were challenged with chronic unpredictable mild stress (CUMS) for 21 days and housed in single cages. The sucrose preference test (SPT), immobility time in the forced swim test (FST), and number in the open field test (OFT) were performed to measure the behavioral changes in the rats. Enzyme-linked immunosorbent assay was used to determine the levels of 5-hydroxytryptamine (5-HT) and brain-derived neurotrophic factor (BDNF) in brain tissue, and the histopathology was performed to evaluate the changes of colon tissue, together with sequencing of the V3-V4 regions of 16S rRNA gene on feces to explore the changes of intestinal flora in the rats. Compared to the control group, the rats in the model group showed notable reductions in body weight, SPF, and number in OFT (P<0.01). Hesperidin was found to ameliorate depression induced by CUMS, as seen by improvements in body weight, SPT, immobility time in FST, and number in OFT (P<0.05 or P<0.01). Regarding neurotransmitters, it was found that at a dose of 50 mg/kg hesperidin treatment upregulated the levels of 5-HT and BDNF in depressed rats (P<0.05). Compared to the control group, the colon tissue of the model group exhibited greater inflammatory cell infiltration, with markedly reduced numbers of goblet cells and crypts and were significantly improved following treatment with hesperidin. Simultaneously, the administration of hesperidin demonstrated a positive impact on the gut microbiome of rats treated with CUMS, such as Shannon index increased and Simpson index decreased (P<0.01), while the abundance of Pseudomonadota and Bacteroidota increased in the hesperidin-treated group (P<0.05). The mechanism responsible for the beneficial effects of hesperidin on depressive behavior in rats may be related to inhibition of the expressions of BDNF and 5-HT and preservation of the gut microbiota.

Early life consumption of a "processed" diet high in advanced glycation end products impairs memory function and alters the gut microbiome in rats

Recent evidence indicates that “ultra-processed” foods constitute ~65% of total energy intake among children in the U.S. The impacts of excessive processed food consumption during development are poorly understood, in part because there are neither clear definitions of, nor a robust classification system accounting for, the complexity of food processing variables and how they interrelate in final food products. Heat treatment, a common form of food processing, can induce the chemical Maillard reaction and lead to foods rich in advanced glycation end products (AGEs). The neurocognitive implications of high levels of AGE consumption, particularly during early life, are unknown. Here, we used a rat model to evaluate the effects of adolescent consumption of a heat-treated diet high in AGEs on cognition and the gut microbiome in adulthood. In a series of studies, rats received either an otherwise healthy AGE-rich diet (AGE rats; AIN-93G diet heated at 160ºC for 60min) or a non-AGE-rich diet (CTL rats; AIN-93G diet without heat treatment) during adolescence (postnatal days 26-60). Metabolic, behavioral, and gut microbiome assessments were performed in adulthood. Results revealed that AGE rats exhibited hippocampal (HPC)-dependent memory deficits relative to CTL rats in the absence of altered body weight, body composition, glucose tolerance, and behavioral measures of anxiety. Administering a drug to break down AGEs (alagebrium; 1mg/kg/day) concomitantly with the heat-treated diet prevented memory impairments, supporting a causal role of AGEs in early life diet-induced HPC dysfunction. Microbiome sequencing analyses revealed that AGE rats had substantially reduced abundance of the bacterial genus Lactococcus relative to controls, and Lactococcus abundance was strongly correlated with memory performance. Administration of Lactococcus lactis by oral gavage (109 colony forming units/day) from PN 26-40 during exposure to the heat-treated diet rescued the AGE diet-induced memory impairments. Collective findings from this work identify a connection between a specific food processing variable (i.e., increased dietary AGEs through heat treatment), the gut microbiome, and impaired neurocognition. This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases under grant DK123423 (awarded to SEK and AAF); the National Institute on Aging through a Postdoctoral Ruth L. Kirschstein National Research Service Award under grant F32AG077932 (awarded to AMRH); and a National Science Foundation Graduate Research Fellowship (awarded to LT). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Gut microbiota in the association between obesity and kidney function decline: a metagenomics-based study in a rat model

Objectives Obesity can induce dysbiosis in the gut microbiota and is considered a separate risk factor for kidney function decline. Nonetheless, the precise function of intestinal microorganisms in facilitating the connection between obesity and kidney function decline remains uncertain. Hence, the objective of this study was to investigate the alterations in the gut microbiota composition that take place during obesity and their correlations with renal function utilizing a rat model. Methods For 20 weeks, 25 Sprague–Dawley rats were fed either a high-fat diet (HFD) or a normal-fat normal diet (ND). Physiological indices, peripheral plasma, kidney tissue, and colon contents were collected for comparison between groups. Metagenomic analysis of intestinal flora was performed. Results The HFD group demonstrated significantly increased levels of creatinine and urea nitrogen in the peripheral blood. Additionally, the HFD rats exhibited a significantly larger glomerular diameter compared to the ND group, accompanied by the presence of glomerulosclerosis, tubular vacuolar transformation, and other pathological changes in certain glomeruli. Metagenomics analysis revealed a notable rise in the prevalence of the Firmicutes phylum within the HFD group, primarily comprising the Rumenococcus genus. Functional analysis indicated that the gut microbiota in the HFD group primarily correlated with infectious diseases, signal transduction, and signaling molecules and interactions. Conclusions This study provides evidence that the consumption of a HFD induces modifications in the composition and functionality of the gut microbiome in rats, which may serve as a potential mechanism underlying the relationship between obesity and the progression of kidney function decline.

S-amlodipine induces liver inflammation and dysfunction through the alteration of intestinal microbiome in a rat model.

S-amlodipine, a commonly prescribed antihypertensive agent, is widely used in clinical settings to treat hypertension. However, the potential adverse effects of long-term S-amlodipine treatment on the liver remain uncertain, given the cautionary recommendations from clinicians regarding its administration in individuals with impaired liver function. To address this, we conducted a study using an eight-week-old male rat model and administered a daily dose of 0.6 ~ 5 mg/kg of S-amlodipine for 7 weeks. Our findings demonstrated that 1.2 ~ 5 mg/kg of S-amlodipine treatment induced liver inflammation and associated dysfunction in rats, further in vitro experiments revealed that the observed liver inflammation and dysfunction were not attributable to direct effects of S-amlodipine on the liver. Metagenome sequencing analysis revealed that S-amlodipine treatment led to alterations in the gut microbiome of rats, with the bloom of E. coli (4.5 ~ 6.6-fold increase) and a decrease in A. muciniphila (1,613.4 ~ 2,000-fold decrease) and B. uniformis (20.6 ~ 202.7-fold decrease), subsequently causing an increase in the gut bacterial lipopolysaccharide (LPS) content (1.4 ~ 1.5-fold increase in feces). S-amlodipine treatment also induced damage to the intestinal barrier and increased intestinal permeability, as confirmed by elevated levels of fecal albumin; furthermore, the flux of gut bacterial LPS into the bloodstream through the portal vein resulted in an increase in serum LPS content (3.3 ~ 4-fold increase). LPS induces liver inflammation and subsequent dysfunction in rats by activating the TLR4 pathway. This study is the first to show that S-amlodipine induces liver inflammation and dysfunction by perturbing the rat gut microbiome. These results indicate the adverse effects of S-amlodipine on the liver and provide a rich understanding of the safety of long-term S-amlodipine administration.

Comparative analysis of the effect of fermented derivatives from Bactrian milk on the gut microbiome

Background:The gut microbiome plays a vital role in maintaining intestinal homeostasis, and its modulation through dietary interventions has garnered considerable interest in improving human health. In this study, we investigated the effect of traditional Kazakh fermented milk products derived from camel milk on the gut microbiome of rats. Objective:The animals were divided into three groups: the Bactrian milk group (BCM), the camel yogurt group (CMY), and the camel cheese group (CMC). Results:After 4 weeks of intervention, the relative abundance of bacterial taxa varied significantly in the BCM and Bactrian milk derivative groups. The CMY group demonstrated a 2-fold increase in the relative abundance of the genus Ligilactobacillus (p=0.032), whereas the CMC group showed a 3-fold decrease (p=0.009). Prevotella_9 exhibited an inverse abundance vector in the CMY (p=0.0005) and CMC (p=0.0001) groups compared to the BCM group. Additionally, 53 metabolic pathways were predicted, each showing varying relative abundances in response to dietary interventions. Notably, the metabolic pathways associated with amines, polyamines, cell structure, fatty acids, and nucleoside and nucleotide biosynthesis underwent the greatest changes. Conclusion:Consumption of camel milk yogurt led to an increase in biodiversity and abundance in the gut microbiota (p&lt;0.01), as evidenced by Shannon and Simpson's indices. In summary, our study demonstrates that fermented camel milk products significantly influence the gut microbiome and metabolic pathways.Keywords: Bactrian camel milk, gut microbiota, rats, yogurt, soft cheese

Effect of 4-thiazolidinone derivative and nimesulide on parietal intestinal microbiota of rats during induced inflammation process in vivo

Nonsteroidal anti-inflammatory drugs, which are widely used in the treatment of diseases accompanied by pain and fever, can cause diseases of the gastrointestinal tract and are associated with disturbances of the intestinal microbiota. The search for new compounds that could affect the community of microorganisms, exhibiting antimicrobial and anti-inflammatory effects, is an important task of modern medicine and veterinary medicine. One of the promising molecules that have such effects are 4-thiazolidinone derivatives. The aim of this study was to analyze the effect of the newly synthesized compound Les6490 and drug nimesulide on the intestinal wall microbiota of rats in vivo under the conditions of Freund’s adjuvant-induced inflammatory process. The study of the effect of the above-mentioned drugs on the intestinal microbiota in vivo was carried out on a biomodel of rats, which were intragastrically administered with the test substances for two weeks. The study material was the parietal mucos of the small intestine, the microbiome of which was studied using 16S rRNA sequencing. Metagenomic analysis made it possible to analyze the types of microorganisms in experimental groups with induced inflammation (groups A and AL) and without it (groups K, L, N). It was established that the composition of the microbiome of the intestinal tract of rats changes under the conditions of induced inflammation and under the action of the compound Les6490 (groups A and L) in comparison with the control group (group K). The influence of Les6490 on the intestinal tract microbiome composition in rats is similar to that of nimesulide, but the effect is more pronounced. The compound Les6490 potentiates the growth of Helicobacter and has an effect against Stenotrophomonas in the group without induced inflammation (group L), but in the group of inflammation (group AL) no such effect is observed. The compound alone (not in inflammation models) leads to increased species diversity of the rat gut microbiome.

Calcium- and Iron-Based Phosphate Binders Impact the Gut Microbiome in Rats with CKD

Calcium- and Iron-Based Phosphate Binders Impact the Gut Microbiome in Rats with CKD

Effect of Clostridium butyricum on the formation of primary choledocholithiasis based on intestinal microbiome and metabolome analysis.

To investigate the function and probable mechanism of Clostridium butyricum in the development of choledocholithiasis. The lithogenic diet group and the lithogenic diet+C. butyricum group were used to develop the choledocholithiasis model. During the experiment, C. butyricum suspension was administered to the rats in the lithogenic diet+C. butyricum group. The findings demonstrated that the C. butyricum intervention decreased the Firmicutes/Bacteroidetes ratio in the colon of experimental animals given a lithogenic diet. The relative levels of Desulfovibrio (0.93%) and Streptococcus (0.38%) fell, whereas Lactobacillus (22.36%), Prevotella (14.09%), and bacteria that produce short-chain fatty acids increased. Finally, 68 distinct metabolic products were found based on nontargeted metabonomics, and 42 metabolic pathways associated to the various metabolites were enriched. We found that C. butyricum decreased the development of choledocholithiasis. It keeps the equilibrium of the rat's gut microbiome intact and lowers the danger of bacterial infections of the gastrointestinal and biliary systems. It is hypothesized that by controlling lipid metabolism, it may also have an impact on the development of cholelithiasis.

Effects of Coenzyme Q10 on the Biomarkers (Hydrogen, Methane, SCFA and TMA) and Composition of the Gut Microbiome in Rats.

The predominant route of administration of drugs with coenzyme Q10 (CoQ10) is administration per os. The bioavailability of CoQ10 is about 2-3%. Prolonged use of CoQ10 to achieve pharmacological effects contributes to the creation of elevated concentrations of CoQ10 in the intestinal lumen. CoQ10 can have an effect on the gut microbiota and the levels of biomarkers it produces. CoQ10 at a dose of 30 mg/kg/day was administered per os to Wistar rats for 21 days. The levels of gut microbiota biomarkers (hydrogen, methane, short-chain fatty acids (SCFA), and trimethylamine (TMA)) and taxonomic composition were measured twice: before the administration of CoQ10 and at the end of the experiment. Hydrogen and methane levels were measured using the fasting lactulose breath test, fecal and blood SCFA and fecal TMA concentrations were determined by NMR, and 16S sequencing was used to analyze the taxonomic composition. Administration of CoQ10 for 21 days resulted in a 1.83-fold (p = 0.02) increase in hydrogen concentration in the total air sample (exhaled air + flatus), a 63% (p = 0.02) increase in the total concentration of SCFA (acetate, propionate, butyrate) in feces, a 126% increase in butyrate (p = 0.04), a 6.56-fold (p = 0.03) decrease in TMA levels, a 2.4-fold increase in relative abundance of Ruminococcus and Lachnospiraceae AC 2044 group by 7.5 times and a 2.8-fold decrease in relative representation of Helicobacter. The mechanism of antioxidant effect of orally administered CoQ10 can include modification of the taxonomic composition of the gut microbiota and increased generation of molecular hydrogen, which is antioxidant by itself. The evoked increase in the level of butyric acid can be followed by protection of the gut barrier function.

You are what you vape: Implications of THC chronic self-administration in changes in the gut microbiome of rats.

Abstract Vaping of cannabis and its constituents, such as Δ9-tetrahydrocanabinol (THC), has been promoted as a safer alternative to smoked cannabis. Nevertheless, chronic effect of THC vaping in gut microbiome modulation and its effect of health and or disease is still largely unknown. Hence, this project intends to study the effect of chronic THC vapor self-administration on changes in the gut microbiome of Sprague-Dawley rats. Animals were randomly assigned to either vehicle vapor (100% propylene glycol [PG]) or THC vapor groups and were allowed to self-administer PG or THC vapor puffs in operant chambers for one hour on intermittent days for a total of nine months. At the end of this period, a subset of rats was tested for anxiety-like behavior using the open field test. Afterwards, rats were euthanized with isoflurane overdose and rapid decapitation. Feces, metabolic and immune organs, and serum were collected at the time of necropsy. Fecal DNA was extracted, and relative bacterial gut abundance was determined sequencing 16S hypervariable region V4. Rats exposed to THC vape show anxiety-like behavior in the open field test, when compared with the PG exposed group. This change in behavior is also accompanied by an imbalance in their Firmicutes/Bacteroides ratio, having less Firmicutes and more Bacteroides, specifically members of the Muribaculaceae family. Currently, the effect of this dysbiosis on immune markers expression, such as: CCL2, IL-6, TNF-a, IFNa, IFNb, MX1 and TRAIL, are being studied to determine if there is any disruption on immune homeostasis caused by altered microbiome abundance. R01DA052859-03S1

Evaluation of the gut microbiome alterations in healthy rats after dietary exposure to different synthetic ZnO nanoparticles

AimsAlthough synthetic ZnO nanoparticles (Nano-ZnO) as an alternative of ZnO compounds have been extensively used such as in livestock production, the increased consuming of Nano-ZnO has raised considerable concerns in environmental pollution and public health. Because of the low digestion of Nano-ZnO, the systematic studies on their interactions with gut microbiota remain to be clarified. Materials and methodsNano-ZnOs were prepared by co-precipitation (ZnO-cp) and high temperature thermal decomposition (ZnO-td) as well as the commercial type (ZnO-s). Transmission electron microscopy (TEM) was used to monitor the morphology of Nano-ZnO. CCK-8 assay was used for cytotoxicity evaluation. Total antioxidant capacity assay, total superoxide dismutase assay, and lipid peroxidation assay were used to evaluate oxidative states of rats. 16S rRNA was used to study the impact of Nano-ZnO on the rat gut microbiome. Key findingsBoth ZnO-cp and ZnO-td exhibited low cytotoxicity while ZnO-s and ZnO-td exhibited prominent antibacterial activities. After a 28-day oral feeding with 1000 mg/kg Zn at dietary dosage, ZnO-s showed slight effect on causing oxidative stress in comparison with that of ZnO-cp and ZnO-td. Results of 16S rRNA sequencing analysis indicated that ZnO-td as a promising short-term nano-supplement can increase probiotics abundances like strains belonged to the genus Lactobacillus and provide the antipathogenic effect. SignificanceThe results of the gut microbiome alteration by synthetic Nano-ZnO not only provide solution to exposure monitoring of environmental hazard, but rationalize their large-scale manufacture as alternative additive in the food chain.

ODP630 Antibiotics Transiently Reduce Circulating Cortisol and Inflammatory Biomarker Levels in Healthy Sprague Dawley Rats

Abstract Introduction Antibiotics are over-used in healthcare, but little is known regarding their effects on cortisol levels in healthy individuals. Furthermore, antibiotics influence the gut microbiome, but the interrelationships between these drugs, cortisol and the microbiome are unknown. Here, we exposed the gut microbiome of rats to a multi-drug antibiotic cocktail and examined effects on circulating cortisol and inflammatory biomarker levels. Methods Male and female (M,F) Sprague-Dawley rats (aged 8 weeks) were housed with phytoestrogen-free bedding, and received a phytoestrogen-free diet with water from glass bottles. Exposed rats received vancomycin (0.5g/L), ampicillin (1g/L), neomycin (1g/L), and metronidazole (1g/L) in their water for 8 days, then returned to normal water for another 13 days. Control rats received normal water throughout the study. Stool and serum samples were collected before starting antibiotics (Abx) (baseline), on day 8 of Abx (AbxD8), and at 13 days post-Abx (PAbxD13). Circulating levels of cortisol and a panel of 12 inflammatory biomarkers were analyzed using MILLIPLEX Hormone Panels and RECYTMAG-65K multiplex panels, respectively. Stool DNA was extracted and 16S V3/V4 libraries were sequenced on an Illumina MiSeq. Operational Taxonomic Unit (OTU) clustering and taxonomic analyses were performed using CLC Microbial Genomics Module v.2.5 (Qiagen). Results A total of 31 rats (M=16, F=15) received Abx and 17 (M=9, F=8) were controls. At baseline, mean cortisol levels were similar between groups (control=34. 08±10.21ng/mL, exposed=35. 05±9.72ng/mL, P=0.96). On AbxD8, cortisol levels decreased in the exposed group relative to controls (control=29.77±9.34ng/mL, exposed=17.35±8.21ng/mL, P&amp;lt;0. 0001), and returned to normal in the exposed group at PAbxD13 (control=33.88±16.65ng/mL, exposed=36.62±8.68ng/mL, P=0.85). Levels of all 12 inflammatory biomarkers were also decreased at AbxD8, and all except MCP1 returned to baseline levels by PAbxD13. Antibiotic exposure resulted in significant decreases in total stool DNA levels in exposed rats relative to controls on AbxD8 (P&amp;lt;0. 0001), but returned to baseline levels by PAbxD13. Stool microbial diversity was also decreased in exposed rats on AbxD8 relative to controls (P=1e-08 and P&amp;lt;0. 0001, respectively), and gut microbiome alterations were seen at multiple taxonomic levels. At PAbxD13, the stool microbiome of exposed rats remained perturbed, and only one phylum, Bacteroidetes, returned to baseline. Abx exposure changed associations between different phyla and levels of cortisol on AbxD8 relative to baseline, and although most of the associations reestablished at PAbxD13, the RA of phylum Proteobacteria was positively associated with levels of cortisol (R=0.243, P=0. 04), as opposed to baseline (R=-0.144, P=0.4). Conclusions Antibiotic exposure results in significant decreases in levels of cortisol as well as inflammatory biomarkers that are associated with perturbations of the gut microbiome, the majority of which returned to baseline following a 13-day antibiotic recovery period. These interrealtionships between cortisol, the gut microbiome and inflammatory biomarkers may have clinical significance. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Modulating effect of Xuanfei Baidu granule on host metabolism and gut microbiome in rats.

Xuanfei Baidu granule (XFBD) is a recommended patented drug for the prevention and treatment of Corona Virus Disease 2019 (COVID-19), which is approved by the National Medical Products Administration. XFBD suppresses the over-activated immune response caused by inflammatory factor storms in COVID-19 infection. The intestine plays a crucial role in the immune system. The mass spectrometry based fecal metabolomics with 16S rDNA sequencing were combined to evaluate the effects of XFBD on host metabolism and gut microbiome. Short-chain fatty acids (SCFAs) contents in fecal matter were quantified by gas chromatography-mass spectrometry (GC-MS). Plasma samples were used to detect immune and inflammatory levels. The results were verified with a rat model of intestinal disorder. Results indicated that XFBD could increase the immune level of Immunoglobulin A (IgA), Immunoglobulin G (IgG) and Immunoglobulin M (IgM) (p < 0.05). The OPLS-DA analysis results showed that a total of 271 differential metabolites (178 up-regulated and 93 down-regulated) were identified based on the VIP ≥1, p < 0.05, FC ≥ 2 and FC ≤ 0.5. The metabolic pathways mainly involved D-Glutamine and D-glutamate metabolism, Arginine biosynthesis, Biotin metabolism, et al. XFBD modified the gut bacteria structure according to the principal component analysis (PCA), that is, 2 phyla, 3 classes, 5 orders, 11 families and 14 genera were significantly different based on taxonomic assignment. In addition, it could partially callback the relative abundance of intestinal microflora in bacterial disorder rats caused by antibiotics. It is suggested that the intervention mechanism of XFBD might be related to the regulation of intestinal flora composition. The evidence obtained in the study provides a useful reference for understanding the mechanism of XFBD.

In Vitro Interactions between Okadaic Acid and Rat Gut Microbiome.

Okadaic acid (OA) is a marine biotoxin associated with diarrhetic shellfish poisoning (DSP), posing some threat to human beings. The oral toxicity of OA is complex, and the mechanism of toxicity is not clear. The interaction between OA and gut microbiota may provide a reasonable explanation for the complex toxicity of OA. Due to the complex environment in vivo, an in vitro study may be better for the interactions between OA and gut microbiome. Here, we conducted an in vitro fermentation experiment of gut bacteria in the presence of 0–1000 nM OA. The remolding ability of OA on bacterial composition was investigated by 16S rDNA sequencing, and differential metabolites in fermentation system with different concentration of OA was detected by LC-MS/MS. We found that OA inhibited some specific bacterial genera but promoted others. In addition, eight possible metabolites of OA, including dinophysistoxin-2 (DTX-2), were detected in the fermentation system. The abundance of Faecalitalea was strongly correlated with the possible metabolites of OA, suggesting that Faecalitalea may be involved in the metabolism of OA in vitro. Our findings confirmed the direct interaction between OA and gut bacteria, which helps to reveal the metabolic process of OA and provide valuable evidence for elucidating the complex toxicity of OA.

Multi-omic Analysis of the Gut Microbiome in Rats with Lithium-Pilocarpine-Induced Temporal Lobe Epilepsy.

Evidence supports that the gut microbiota and bacteria-dependent metabolites influence the maintenance of epileptic brain activity. However, the alterations in the gut microbiota between epileptic versus healthy individuals are poorly understood. We used a multi-omic approach to evaluate the changes in the composition of gut metagenome as well in the fecal metabolomic profile in rats before and after being submitted to status epilepticus (SE)-induced temporal lobe epilepsy (TLE). The 16S ribosomal RNA (rRNA) sequencing of fecal samples coupled to bioinformatic analysis revealed taxonomic, compositional, and functional shifts in epileptic rats. The species richness (Chao1 index) was significantly lower in the post-TLE group, and the β-diversity analysis revealed clustering separated from the pre-TLE group. The taxonomic abundance analysis showed a significant increase of phylum Desulfobacterota and a decrease of Patescibacteria in the post-TLE group. The DESEq2 and LEfSe analysis resulted in 18 genera significantly enriched between post-TLE and pre-TLE groups at the genus level. We observed that epileptic rats present a peculiar metabolic phenotype, including a lower concentration of D-glucose and L-lactic acid and a higher concentration of L-glutamic acid and glycine. The microbiota-host metabolic correlation analysis showed that the genera differentially abundant in post-TLE rats are associated with the altered metabolites, especially the proinflammatory Desulfovibrio and Marvinbryantia, which were enriched in epileptic animals and positively correlated with these excitatory neurotransmitters and carbohydrate metabolites. Therefore, our data revealed a correlation between dysbacteriosis in epileptic animals and fecal metabolites that are known to be relevant for maintaining epileptic brain activity by enhancing chronic inflammation, an excitatory-inhibitory imbalance, and/or a metabolic disturbance. These data are promising and suggest that targeting the gut microbiota could provide a novel avenue for preventing and treating acquired epilepsy. However, the causal relationship between these microbial/metabolite components and the SRS occurrence still needs further exploration.

Profiling of d-alanine production by the microbial isolates of rat gut microbiota.

d-alanine (d-Ala) and several other d-amino acids (d-AAs) act as hormones and neuromodulators in nervous and endocrine systems. Unlike the endogenously synthesized d-serine in animals, d-Ala may be from exogenous sources, e.g., diet and intestinal microorganisms. However, it is unclear if the capability to produce d-Ala and other d-AAs varies among different microbial strains in the gut. We isolated individual microorganisms of rat gut microbiota and profiled their d-AA production in vitro, focusing on d-Ala. Serial dilutions of intestinal contents from adult male rats were plated on agar to obtain clonal cultures. Using MALDI-TOF MS for rapid strain typing, we identified 38 unique isolates, grouped into 11 species based on 16S rRNA gene sequences. We then used two-tier screening to profile bacterial d-AA production, combining a d-amino acid oxidase-based enzymatic assay for rapid assessment of non-acidic d-AA amount and chiral LC-MS/MS to quantify individual d-AAs, revealing 19 out of the 38 isolated strains as d-AA producers. LC-MS/MS analysis of the eight top d-AA producers showed high levels of d-Ala in all strains tested, with substantial inter- and intra-species variations. Though results from the enzymatic assay and LC-MS/MS analysis aligned well, LC-MS/MS further revealed the existence of d-glutamate and d-aspartate, which are poor substrates for this enzymatic assay. We observed large inter- and intra-species variation of d-AA production profiles from rat gut microbiome species, demonstrating the importance of chemical profiling of gut microbiota in addition to sequencing, furthering the idea that microbial metabolites modulate host physiology.

The impacts of bovine milk, soy beverage, or almond beverage on the growing rat microbiome.

BackgroundMilk, the first food of mammals, helps to establish a baseline gut microbiota. In humans, milk and milk products are consumed beyond infancy, providing comprehensive nutritional value. Non-dairy beverages, produced from plant, are increasingly popular as alternatives to dairy milk. The nutritive value of some plant-based products continues to be debated, whilst investigations into impacts on the microbiome are rare. The aim of this study was to compare the impact of bovine milk, soy and almond beverages on the rat gut microbiome. We previously showed soy and milk supplemented rats had similar bone density whereas the almond supplemented group had compromised bone health. There is an established link between bone health and the microbiota, leading us to hypothesise that the microbiota of groups supplemented with soy and milk would be somewhat similar, whilst almond supplementation would be different.MethodsThree-week-old male Sprague Dawley rats were randomly assigned to five groups (n = 10/group) and fed ad libitum for four weeks. Two control groups were fed either standard diet (AIN-93G food) or AIN-93G amino acids (AA, containing amino acids equivalent to casein but with no intact protein) and with water provided ad libitum. Three treatment groups were fed AIN-93G AA and supplemented with either bovine ultra-heat treatment (UHT) milk or soy or almond UHT beverages as their sole liquid source. At trial end, DNA was extracted from caecum contents, and microbial abundance and diversity assessed using high throughput sequencing of the V3 to V4 variable regions of the 16S ribosomal RNA gene.ResultsAlmost all phyla (91%) differed significantly (FDR < 0.05) in relative abundance according to treatment and there were distinct differences seen in community structure between treatment groups at this level. At family level, forty taxa showed significantly different relative abundance (FDR < 0.05). Bacteroidetes (Bacteroidaceae) and Firmicutes populations (Lactobacillaceae, Clostridiaceae and Peptostreptococcaceae) increased in relative abundance in the AA almond supplemented group. Supplementation with milk resulted in increased abundance of Actinobacteria (Coriobacteriaceae and Bifidobacteriaceae) compared with other groups. Soy supplementation increased abundance of some Firmicutes (Lactobacilliaceae) but not Actinobacteria, as previously reported by others.ConclusionSupplementation with milk or plant-based drinks has broad impacts on the intestinal microbiome of young rats. Changes induced by cow milk were generally in line with previous reports showing increased relative abundance of Bifidobacteriacea, whilst soy and almond beverage did not. Changes induced by soy and almond drink supplementation were in taxa commonly associated with carbohydrate utilisation. This research provides new insight into effects on the microbiome of three commercially available products marketed for similar uses.

The influence of different types of ß-glucans on the gut microbiota of rats fed milk gels

• The frequency of Bacteroides depends on the acidity of the product. • Body weight gain was significantly correlated with the abundance of Streptococcus sp. • β-glucans resulted in a decrease in Lactobacillus frequency. • Oat ß-glucan contributed to a higher Clostridium sensu stricto and Blautia counts. The effect of glucans on gut microbiota functions is still unclear. Therefore, this study was undertaken to describe the influence of structurally different ß-glucans (oat ß-glucan, curdlan and scleroglucan) on the structure of the gut microbiome in rats. The structure of intestinal microbiota was evaluated by high-throughput sequencing of the16S rRNA gene. Firmicutes and Bacteroidetes were the dominant bacterial phyla in all animals. Oat ß-glucan contributed to a higher prevalence of bacterial genera Clostridium sensu stricto and Blautia , whereas curdlan increased the relative abundance of Akkermansia muciniphila. A positive correlation was noted between the relative abundance of Streptococcus bacteria and the growth rate of rats. The present study demonstrated that the consumption of non-acidified milk gels or acidified milk gels with a β-glucan dose recommended by EFSA (3.0–4.0 g per day) for 28 days did not induce significant changes in the structure of the gut microbiome in rats.

Red Wheat Alters Colon Cancer Risk, Oxidative Stress, and the Gut Microbiome

ObjectivesRed wheat, the class of wheat used to make yeast bread products, is associated with reductions in colon cancer biomarkers, regardless of refinement state. We hypothesized that red wheat as well as the phenol-rich aleurone and testa layers of red wheat would reduce colonic precancerous lesions and oxidative stress, and beneficially modulate the gut microbiome in rats with diet-induced obesity. MethodsRats were divided into seven groups (12/group) and fed a normal fat diet (NFD), high-fat diet (50% of total kcal as fat, HFD), whole red wheat + HFD (whR + HFD), refined red wheat + HFD (refR + HFD), refined white wheat + HFD (refW + HFD), aleurone layer + HFD (AL + HFD), or testa layer + HFD (TL + HFD). After a 14-day adaptation period, rats received two i.p. injections of the colon-specific carcinogen 1,2-dimethylhydrazine (DMH), administered one week apart. Sixty-three days after the second injection, colons were harvested and precancerous lesions (aberrant crypt foci, ACF) were enumerated. Staining intensity of 3-nitrotyrosine (3-NT) was determined immunohistochemically in distal colon tissue. Microbial DNA from cecal contents was sequenced using a 16S rRNA metagenomic approach. Differences in alpha and beta diversity, and microbial abundances were determined. ResultsCompared to the NFD, the HFD had a greater number of ACF, regardless of size (i.e., AC/ACF). The refR + HFD had significant reductions in medium ACF (3–5 AC/ACF; 2.62 vs. 4.28), large ACF (≥6 AC/ACF; 0.06 vs. 0.45), ACF multiplicity (1.58 vs. 2.01) and 3-NT (% positivity per ACF; 2.06% vs. 4.51%) compared to the HFD. All diets containing wheat reduced large ACF number. The TL + HFD and AL + HFD demonstrated trends for reducing ACF with 8 AC (0.06 vs. 0.18) and 3-NT (2.22% vs. 4.51%), respectively, compared to the HFD. Beta diversity significantly differed between diet groups (R2 = 0.27, P = 0.001), and there was greater abundance of Faecalitalea, Fusicatenibacter, and Lactobacillus in the cecal contents of rats fed wheat-containing diets. ConclusionsRed wheat reduces precancerous lesions, oxidative stress, and beneficially modulates the gut microbiome relative to a non-wheat diet. The phenol-rich testa and aleurone layers alone had little influence on these outcomes. Funding SourcesNDSU Collaborative Seed Grant Program.

Effects of Heat Stress on Gut Microbiome in Rats

Gut microbiome, as the largest and most important micro-ecosystem, plays a critical role in health. The purpose of this study was to evaluate whether heat stress modulates the composition and diversity of the gut microbiome in rats. The heat stress model was prepared in rats with the heating temperature maintained at 35–38°C. Cecum contents were collected after heat stress for 3 h and days 1, 3 and 7. Total DNA was extracted for 16 S rRNA sequencing and analysis of intestinal microbiome composition and diversity. The study showed that the composition of the intestinal microbiome of heat stress group was changed. And the heat stress modulated key phylotypes of gut microbiota at the level of phylum and genus. In particular, the genus of Lactobacillus and Bacteroides were significantly reduced, whereas the Oscillospira and Clostridium were increased by heat stress. Meanwhile, the rats under the heat stress encountered the change in carbohydrate metabolism, amino acid metabolism, and membrane transport to defense against stress. Taken together, the composition and structure of gut microbiome were affected by heat stress and some key phylotypes were also significantly altered. We conclude that the heat stress could impact multiple biological functions, via altering the gut microbiome.