Mutual interaction between gut microbiota and protein/amino acid metabolism for host mucosal immunity and health

Astaxanthin supplementation mitigated intestinal damage and immunity in overfed Pekin ducks by regulating gut morphology, intestinal inflammation, and antioxidant balance

This study explored the impact of astaxanthin (AST) supplementation on growth performance, serum lipid profile, gut morphology, and antioxidant and immune function in the intestinal mucosa of Pekin ducks subjected to overfeeding. A total of 150 male Pekin ducks at one day of age were randomly allotted into five treatment groups with five replicates of six ducks each. The control group and ad libitum group (ALG) received a basal diet while others received basal diets supplemented with AST at 40 mg/kg (Low-dose group [LDG]), 80 mg/kg (medium-dose group [MDG]), and 120 mg/kg (high-dose group [HDG]). After 1 to 14 d on basal diets (brooding phase), the ducks were assigned to the dietary treatment groups for 15 to 38 d (Grower phase) and 39 to 42 d (overfeeding period). Results indicated that AST supplementation improved final body weight and weight gain at both the grower and overfeeding phases (P < 0.05). Overfeeding increased the serum lipid level, altered intestinal morphology, and led to higher expression of pro-inflammatory factors and oxidative stress biomarkers while reducing antioxidant enzyme activity, associated gene expression, and anti-inflammatory factors in the duodenal and jejunal mucosa (P < 0.05). Additionally, overfeeding caused increased apoptotic cell counts in the duodenal and jejunal mucosa of the control group (P < 0.05), culminating in intestinal tissue damage and dysfunction. Dietary supplementation of AST mitigated these adverse effects, alleviated intestinal damage and promoted gut health. It exerted a hypolipidemic effect, improved villi morphometrics in the duodenum, jejunum, and ileum, and enhanced the levels of interleukin-4 (IL-4), soluble tumor necrosis factor-alpha receptor (sTNFαR), and transforming growth factor-beta (TGF-β) (P < 0.05). It also increased the activities of antioxidant enzymes and the mRNA expression of key antioxidant-related genes, including nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione S-transferases (GSTs), and glutamate-cysteine ligase catalytic subunit (GCLC) (P < 0.05). Moreover, it reduced the expression of pro-inflammatory factors, oxidative stress biomarkers such as reactive oxygen species (ROS) and malondialdehyde (MDA), and the number of apoptotic cells in the duodenal and jejunal mucosa (P < 0.05). Immunoglobulin secretion and mucosal immunity were also significantly improved with AST supplementation (P < 0.05). Variations among the AST dietary groups suggest that a medium dosage of 80 mg/kg could effectively mitigate intestinal damage from overfeeding while enhancing growth performance, antioxidant defences, and immune responses. Our results would provide a theoretical reference for using AST as a nutritional strategy to enhance gut health in ducks exposed to overfeeding.

Microbes with higher metabolic independence are enriched in human gut microbiomes under stress

A wide variety of human diseases are associated with loss of microbial diversity in the human gut, inspiring a great interest in the diagnostic or therapeutic potential of the microbiota. However, the ecological forces that drive diversity reduction in disease states remain unclear, rendering it difficult to ascertain the role of the microbiota in disease emergence or severity. One hypothesis to explain this phenomenon is that microbial diversity is diminished as disease states select for microbial populations that are more fit to survive environmental stress caused by inflammation or other host factors. Here, we tested this hypothesis on a large scale, by developing a software framework to quantify the enrichment of microbial metabolisms in complex metagenomes as a function of microbial diversity. We applied this framework to over 400 gut metagenomes from individuals who are healthy or diagnosed with inflammatory bowel disease (IBD). We found that high metabolic independence (HMI) is a distinguishing characteristic of microbial communities associated with individuals diagnosed with IBD. A classifier we trained using the normalized copy numbers of 33 HMI-associated metabolic modules not only distinguished states of health vs IBD, but also tracked the recovery of the gut microbiome following antibiotic treatment, suggesting that HMI is a hallmark of microbial communities in stressed gut environments.

Evaluation of biomarkers for intestinal damage in pediatric acute lymphoblastic leukemia

Intestinal damage (ID) leads to bacterial translocation and bloodstream infections-the common cause of non-relapse mortality in childhood acute lymphoblastic leukemia (ALL). This study evaluated ID over ALL induction and the significance of body mass index (BMI) for its development and identified biomarkers reflecting chemotherapy-induced ID. The composite biomarker panel included 37 plasma amino acids, urea, ammonia, fecal calprotectin (fCLP), absolute neutrophil count (ANC), C-reactive protein, and albumin. We prospectively assessed 45 children treated according to the ALLTogether protocol in 2020-2024. Analysis and sample collection were performed on days 1, 8, 15, 22, and 29 of the protocol. The obtained values were compared between the ID and non-ID groups. 40% of patients (18/45) had grade I-III ID which was more pronounced on day 22 of induction when the ANC increased from its lowest point. Age younger than 5.5 years at a diagnosis was a significant prognostic factor for ID. Decreasing BMI and concentrations of citrulline, taurine, cystine, phosphoethanolamine, A-aminobutyric acid, B-alanine, and albumin suggest progressive ID in children treated due to ALL. No difference in ANC and fCLP was found between patients with and without ID, but fCLP levels start to rise simultaneously as the most intense ID is observed. In conclusion, assessing nutritional status and prospective evaluation of biomarkers may provide valuable information on treatment-related ID.

Evaluating the impact of temperatures and exposure times on probiotics viability under pre- and post- technological processes

Microorganisms such as probiotic yeasts and lactic acid bacteria are capable of surviving-and in some cases thriving-under challenging conditions, including varying feed compositions, moisture levels, and high temperatures typically encountered during feed processing, such as steam pelleting. The primary objective of this study was to evaluate the effect of different temperatures and exposure times on the viability of yeast- and lactic acid bacteria-based probiotics in aqueous solution. Following this, the probiotics were freeze-dried and incorporated separately into a feed matrix to assess their survival during both simulated and actual pelleting processes. In addition, a comparative analysis was conducted to evaluate the viability of Saccharomyces boulardii RC009 under two different drying methods: freeze-drying and fluidized bed drying. All strains evaluated exhibited thermoresistance across the tested temperature range, with yeasts demonstrating greater resistance than bacterial strains. Notably, Saccharomyces spp. and Pediococcus pentosaceus showed the highest thermal tolerance. This enhanced resilience may be attributed to the presence of heat shock proteins (Hsps) and antioxidant defense systems in yeasts, and the production of heat-stable exopolysaccharides (EPS-DPS) in P. pentosaceus. Building on these findings, the freeze-dried probiotics were successfully integrated into a feed matrix and subjected to granulation processes to evaluate their viability post-processing. To our knowledge, this is the first study to systematically assess the impact of temperature and exposure time on probiotic viability during both pre- and post-technological treatments in the context of feed production.

Enriched pathways in gut microbiome predict response to immune checkpoint inhibitor treatment across demographic regions and various cancer types

Understanding the effect of gut microbiota function on immune checkpoint inhibitor (ICI) responses is urgently needed. Here, we integrated 821 fecal metagenomes from 12 datasets to identify differentially abundant genes and construct random forest models to predict ICI response. Gene markers demonstrated excellent predictive performance, with an average area under the curve (AUC) of 0.810. Pathway analyses revealed that quorum sensing (QS), ABC transporters, flagellar assembly, and amino acid biosynthesis pathways were enriched between responders (R) and non-responders (NRs) across 12 datasets. Furthermore, luxS, manA, fliC, and trpB exhibited consistent changes between R and NR across 12 datasets. Follow-up microbiota transplant experiments showed that inter-species signaling by different QS autoinducer-2 (AI-2) molecules (synthesized by luxS) can act on overall community function to promote the colonization of Akkermansia muciniphila, which is associated with superior ICI responses. Together, our data highlight the role of gut microbiota function in modulating the microbiome and antitumor immunity.

The role of colonic microbiota amino acid metabolism in gut health regulation

The human gut microbiota plays a critical role in maintaining host homeostasis through metabolic activities. Among these, amino acid (AA) metabolism by the microbiota in the large intestine is highly heterogeneous and relevant to host health. Despite increasing interest, microbial AA metabolism remains relatively unexplored. This review highlights recent advances in colonic microbial AA metabolism, including auxotrophies, AA synthesis, and dissimilatory AA metabolites, and their implications in gut health, focusing on major gastrointestinal diseases including colorectal cancer, inflammatory bowel disease, and irritable bowel syndrome.

Overall biomass yield on multiple nutrient sources

Microorganisms primarily utilize nutrients to generate biomass and replicate. When a single nutrient source is available, the produced biomass typically increases linearly with the initial amount of that nutrient. This linear trend can be accurately predicted by "black box models", which conceptualize growth as a single chemical reaction, treating nutrients as substrates and biomass as a product. However, natural environments usually present multiple nutrient sources, prompting us to extend the black box framework to incorporate catabolism, anabolism, and biosynthesis of biomass precursors. This modification allows for the quantification of co-utilization effects among multiple nutrients on microbial biomass production. The extended model differentiates between different types of nutrients: non-degradable nutrients, which can only serve as a biomass precursor, and degradable nutrients, which can also be used as an energy source. We experimentally demonstrated using Escherichia coli that, in contrast to initial model predictions, different nutrients affect each other's utilization in a mutually dependent manner; i.e., for some combinations, the produced biomass was no longer proportional to the initial amounts of nutrients present. To account for these mutual effects within a black box framework, we phenomenologically introduced an interaction between the metabolic processes involved in utilizing the nutrient sources. This phenomenological model qualitatively captures the experimental observations and, unexpectedly, predicts that the total produced biomass is influenced not only by the combination of nutrient sources but also by their relative initial amounts - a prediction we subsequently validated experimentally. Moreover, the model identifies which metabolic processes - catabolism, anabolism, or precursor biosynthesis-is affected in each specific nutrient combination, offering insights into microbial metabolic coordination.

Microbiota-derived 3-Methyl-L-histidine mediates the proatherogenic effect of high chicken protein diet

Diet rich in chicken protein has gained a widespread popularity for its profound effect on weight loss and glycemic control; however, its long-term effect on cardiovascular health and the underlying mechanisms remains obscure. Here, we demonstrated that higher intake of chicken protein was an independent risk factor for sub-clinical atherosclerosis. Adherence to high chicken protein diet (HCD) alleviated excessive weight gain and glycemic control regardless of the presence of gut microbiota in apolipoprotein E-deficient mice. In contrast, long-term HCD administration enhanced intestinal cholesterol absorption and accelerated atherosclerotic plaque formation in a gut microbiota-dependent manner. Integrative analysis of 16S rDNA sequencing and metabolomics profiling identified 3-Methyl-L-histidine (3-MH), resulting from an enrichment of Lachnospiraceae, as the key microbial effector to the atherogenic effect of HCD. Mechanistically, 3-MH facilitated the binding of hepatocyte nuclear factor 1A (HNF1A) to the promoter of NPC1-like intracellular cholesterol transporter 1 (NPC1L1), whereas inhibition of HNF1A-NPC1L1 axis abolished the atherogenic effect of 3-MH. Our findings uncovered a novel link between microbiota-derived 3-MH and disturbed cholesterol homeostasis, which ultimately accelerated atherosclerosis, and argued against the recommendation of HCD as weight loss regimens considering its adverse role in vascular health.

Maternal obesity changes the small intestine endocannabinoid system and fecal metabolites of weanling rats associated with reduced intestinal permeability and impaired glucose homeostasis

The small intestine, including the endocannabinoid system (ECS), regulates the energy homeostasis. If maternal obesity modifies the intestinal ECS of the offspring favoring metabolic disorders throughout life is unexplored. Regardless maternal insults, overaction of the ECS has been related to obesity, mainly via type 1 cannabinoid receptor (CB1) signaling, while type 2 cannabinoid receptor (CB2) signaling and the endocannabinoid-like compounds, such as oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), have been associated with anti-inflammatory effects. We hypothesized that maternal obesity changes the ECS in the small intestine of weanling rat offspring in a sex-specific manner associated with altered fecal metabolites. Female rats received a control diet (C; 9% fat) or an obesogenic diet (OD; 37.2% fat, 11.8% sucrose) 9 weeks before mating, gestation and lactation. Offspring were euthanized at weaning. Maternal obesity increased CB2 protein content and mRNA levels of monocyte chemoattractant protein-1 in the small intestine in male offspring, while decreased fecal content of PEA and OEA in both sexes. Maternal obesity decreased gut permeability, but impaired glycemic homeostasis. Concerning fecal levels of γ-aminobutyric acid, amino acids and hypoxanthine, maternal obesity induced a fecal signature related to inflammatory and glycemic homeostasis impairment and dysbiosis. Maternal obesity induced intestinal inflammation and the signaling of CB2, PEA, and OEA might be part of a counter-regulatory response, contributing to reduced gut permeability, but not enough to avoid overweight and glycemic impairment in the offspring at weaning. Our findings provide molecular insights into the intestinal and fecal biomarkers for metabolic disorders.

Optimizing male layer chicken performance and health with probiotic supplementation: A sustainable alternative to antibiotic growth promoters

Background

The rising global concern over antibiotic resistance has heightened scrutiny of antibiotic growth promoters (AGPs) in poultry farming, prompting a shift toward alternative feed additives to ensure sustainable and safe poultry production. This trend aligns with the increasing demand for free-range and naturally raised chicken meat in various regions, including Indonesia. In response, Indonesian breeders have turned to medium-sized male layer chickens (MLCs) as substitutes for traditional free-range chickens. This practice, coupled with the need to replace AGPs, highlights the critical importance of exploring innovative and natural solutions to enhance poultry growth and health.

Aim

This study investigated the effects of probiotics as an alternative to AGPs on the growth performance, carcass traits, and immune organs of male ISA Brown layer chickens.

Methods

The 180-day-old male ISA Brown layer chickens were used for the study. The intervention included six treatments. T1 basal feed, T2 2.5 g AGP/kg feed, T3 1 ml probiotic/kg feed, T4 3 ml probiotic/kg feed, T5 4 ml probiotic/kg feed, and T6 5 ml probiotic/kg feed. Probiotics used were Lactobacillus acidophilus, Bifidobacterium sp., and Lactobacillus plantarum at a concentration of 1.2 × 109 CFU/ml. The feeding trial lasted for 21 days for chickens aged 21-42 days, assessing growth performance [body weight, feed consumption, digestibility, and feed conversion ratio (FCR)], carcass traits, non-edible organs, and immune organs.

Results

The findings demonstrate that probiotic supplementation significantly outperformed the AGP-treated group (T2) in enhancing growth performance, carcass weight, pectoral weight development, FCR, internal and immune organ weights, nutrient intake, and digestibility. While AGPs showed improvements over the control (T1), probiotic- supplemented groups, particularly T6, achieved superior results across all parameters, indicating that probiotics are not only a viable alternative to AGPs but also a more effective and sustainable approach for poultry production.

Conclusion

The probiotics used in the study at 4 and 5 ml/kg of feed significantly enhanced the performance, immune organ development, and carcass attributes of MLCs, demonstrating their effectiveness as a viable alternative to AGPs. These findings highlight the potential of probiotics to improve poultry production sustainability by reducing reliance on antibiotics, enhancing growth and health outcomes, and promoting animal welfare through natural and efficient dietary interventions.

The Human Gut Microbiota: A Dynamic Biologic Factory

The human body constitutes a living environment for trillions of microorganisms, which establish the microbiome and, the largest population among them, reside within the gastrointestinal tract, establishing the gut microbiota. The term "gut microbiota" refers to a set of many microorganisms [mainly bacteria], which live symbiotically within the human host. The term "microbiome" means the collective genomic content of these microorganisms. The number of bacterial cells within the gut microbiota exceeds the host's cells; collectively and their genes quantitatively surpass the host's genes. Immense scientific research into the nature and function of the gut microbiota is unraveling its roles in certain human health activities such as metabolic, physiology, and immune activities and also in pathologic states and diseases. Interestingly, the microbiota, a dynamic ecosystem, inhabits a particular environment such as the human mouth or gut. Human microbiota can evolve and even adapt to the host's unique features such as eating habits, genetic makeup, underlying diseases, and even personalized habits. In the past decade, biologists and bioinformaticians have concentrated their research effort on the potential roles of the gut microbiome in the development of human diseases, particularly immune-mediated diseases and colorectal cancer, and have initiated the assessment of the impact of the gut microbiome on the host genome. In the present chapter, we focus on the biological features of gut microbiota, its physiology as a biological factory, and its impacts on the host's health and disease status.

Therapeutic potential of Parabacteroides distasonis in gastrointestinal and hepatic disease

Increasing evidences indicate that the gut microbiota is involved in the development and therapy of gastrointestinal and hepatic disease. Imbalance of gut microbiota occurs in the early stages of diseases, and maintaining the balance of the gut microbiota provides a new strategy for the treatment of diseases. It has been reported that Parabacteroides distasonis is associated with multiple diseases. As the next-generation probiotics, several studies have demonstrated its positive regulation on the gastrointestinal and hepatic disease, including inflammatory bowel disease, colorectal cancer, hepatic fibrosis, and fatty liver. The function of P. distasonis and its metabolites mainly affect host immune system, intestinal barrier function, and metabolic networks. Manipulation of P. distasonis with natural components lead to the protective effect on enterohepatic disease. In this review, the metabolic pathways regulated by P. distasonis are summarized to illustrate its active metabolites and their impact on host metabolism, the role and action mechanism in gastrointestinal and hepatic disease are discussed. More importantly, the natural components can be used to manipulate P. distasonis as treatment strategies, and the challenges and perspectives of P. distasonis in clinical applications are discussed.

Leucine-Enriched Diet Reduces Fecal MPO but Does Not Protect Against DSS Colitis in a Mouse Model of Crohn's Disease-like Ileitis

Understanding the complex link between inflammation, gut health, and dietary amino acids is becoming increasingly important in the pathophysiology of inflammatory bowel disease (IBD). This study tested the hypothesis that a leucine-rich diet could attenuate inflammation and improve gut health in a mouse model of IBD. Specifically, we investigated the effects of a leucine-rich diet on dextran sulfate sodium (DSS)-induced colitis in germ-free (GF) SAMP1/YitFC (SAMP) mice colonized with human gut microbiota (hGF-SAMP). hGF-SAMP mice were fed one of four different diets: standard mouse diet (CHOW), American diet (AD), leucine-rich AD (AD + AA), or leucine-rich CHOW diet (CH + AA). Body weight, myeloperoxidase (MPO) activity, gut permeability, colonoscopy scores, and histological analysis were measured. Mice on a leucine-rich CHOW diet showed a decrease in fecal MPO prior to DSS treatment as compared to those on a regular diet (p > 0.05); however, after week five, prior to DSS, this effect had diminished. Following DSS treatment, there was no significant difference in gut permeability, fecal MPO activity, or body weight changes between the leucine-supplemented and control groups. These findings suggest that while a leucine-rich diet may transiently affect fecal MPO levels in hGF-SAMP mice, it does not confer protection against DSS-induced colitis symptoms or mitigate inflammation in the long term.

Immune-enhancing effect of Weizmannia coagulans BCG44 and its supernatant on cyclophosphamide-induced immunosuppressed mice and RAW264.7 cells via the modulation of the gut microbiota

We established a model of cyclophosphamide (CTX)-induced immunosuppressed mice and RAW264.7 cells to assess the effectiveness of W. coagulans BCG44 and its supernatant in enhancing immune function and modulating the gut microbiota. W. coagulans BCG44 and its supernatant restored Th17/Treg balance and alleviated gut inflammation by elevating the expression of interleukin-10 (IL-10) and decreasing IL-6 and toll-like receptor 4 (TLR4). Meanwhile, W. coagulans BCG44 and its supernatant downregulated the levels of lipopolysaccharide and D-lactic acid while increasing the expression of tight junction proteins (ZO-1 and occludin) and goblet cells/crypts to ameliorate mucosal damage. W. coagulans BCG44 and its supernatant may restore the gut microbiota in the immunosuppressed mice by regulating keystone species (Lactobacillus and Lachnospiraceae). PICRUSt2 function prediction and BugBase analysis showed that W. coagulans BCG44 and its supernatant significantly down-regulated American trypanosomiasis and potentially_pathogenic. In addition, under normal versus inflamed culture conditions, stimulation of RAW246.7 cells with W. coagulans BCG44 supernatant activated immune response with increasing proliferation ability and the gene expression of IL-10 while decreasing TLR4. Metabolites in the W. coagulans BCG44 supernatant included arginine, tyrosine, solamargine, tryptophan, D-mannose, phenyllactic acid, and arachidonic acid. Collectively, these findings suggested that W. coagulans BCG44 and its supernatant possess potential immunomodulatory activity and modulate gut microbiota dysbiosis in the CTX-induced immunosuppressed mice.

Dietary protein modulates intestinal dendritic cells to establish mucosal homeostasis

Dietary proteins are taken up by intestinal dendritic cells (DCs), cleaved into peptides, loaded to major histocompatibility complexes, and presented to T cells to generate an immune response. Amino acid (AA)-diets do not have the same effects because AAs cannot bind to major histocompatibility complex to activate T cells. Here, we show that impairment in regulatory T cell generation and loss of tolerance in mice fed a diet lacking whole protein is associated with major transcriptional changes in intestinal DCs including downregulation of genes related to DC maturation, activation and decreased gene expression of immune checkpoint molecules. Moreover, the AA-diet had a profound effect on microbiome composition, including an increase in Akkermansia muciniphilia and Oscillibacter and a decrease in Lactococcus lactis and Bifidobacterium. Although microbiome transfer experiments showed that AA-driven microbiome modulates intestinal DC gene expression, most of the unique transcriptional change in DC was linked to the absence of whole protein in the diet. Our findings highlight the importance of dietary proteins for intestinal DC function and mucosal tolerance.

In Vitro Human Gastrointestinal Digestibility and Colonic Fermentation of Wheat Sourdough and Yeast Breads

Bread can vary in textural and nutritional attributes based on differences in the bread making process (e.g., flour type, fermentation agent, fermentation time). Four bread recipes (BRs) made with sourdough preferments (BR1, white flour; BR2, whole grain flour) or regular yeast breads (BR3, white flour; BR4, whole grain flour) were evaluated for texture, digestibility, and their effect on the metabolic activity and composition of the gut microbiota using texture profile analysis (TPA) coupled with in vitro upper gastrointestinal (GIT) digestion and colonic fermentation (Colon-on-a-plate™ model), using fecal samples from eight healthy human donors. TPA revealed significantly higher values for hardness, fracturability, gumminess, and chewiness, and significantly lower values for springiness, cohesiveness, and resilience with whole grain versus white breads (all p < 0.001); values for springiness, cohesiveness, and resilience were significantly higher for sourdough versus yeast bread (p < 0.001). Nutrient composition and bioaccessibility were generally comparable between sourdough and yeast bread with similar flours. Following simulation of upper GIT digestion, all BRs demonstrated good digestibility of minerals, carbohydrates, and proteins. Colonic fermentation revealed changes in gut microbiota composition, significant increases in short-chain fatty acids, and a significant decrease in branched short-chain fatty acids with all BRs versus a blank. Overall, new insights into wheat bread digestibility and colonic fermentation were provided, which are important aspects to fully characterize bread nutritional profile and potential.

Therapeutic modulation of the kynurenine pathway in severe mental illness and comorbidities: A potential role for serotonergic psychedelics

Mounting evidence points towards a crucial role of the kynurenine pathway (KP) in the altered gut-brain axis (GBA) balance in severe mental illness (SMI, namely depression, bipolar disorder, and schizophrenia) and cardiometabolic comorbidities. Preliminary evidence shows that serotonergic psychedelics and their analogues may hold therapeutic potential in addressing the altered KP in the dysregulated GBA in SMI and comorbidities. In fact, aside from their effects on mood, psychedelics elicit therapeutic improvement in preclinical models of obesity, metabolic syndrome, and vascular inflammation, which are highly comorbid with SMI. Here, we review the literature on the therapeutic modulation of the KP in the dysregulated GBA in SMI and comorbidities, and the potential application of psychedelics to address the altered KP in the brain and systemic dysfunction underlying SMI and comorbidities. Psychedelics might therapeutically modulate the KP in the altered GBA in SMI and comorbidities either directly, via altering the metabolic pathway by influencing the rate-limiting enzymes of the KP and affecting the levels of available tryptophan, or indirectly, by affecting the gut microbiome, gut metabolome, metabolism, and the immune system. Despite promising preliminary evidence, the mechanisms and outcomes of the KP modulation with psychedelics in SMI and systemic comorbidities remain largely unknown and require further investigation. Several concerns are discussed surrounding the potential side effects of this approach in specific cohorts of individuals with SMI and systemic comorbidities.

Importance of diet and intestinal microbiota in the prevention of colorectal cancer - colonoscopy early screening diagnosis

Colorectal cancer is a term used to describe colon and rectal cancer, which is the third most common type of cancer. A MEDLINE and PubMed search resulted in the inclusion of manuscripts written in the last 10 years, using keywords relevant to the topic of the manuscript. By analyzing the aim of the searched studies and manuscripts, adequate articles were included that described the stated problem. The frequency of colorectal cancer varies with climate, nutrition, and many other factors, primarily endogenous, hereditary, intestinal microbiome, as well as external factors, such as exposure of the individual to stress, and bad eating habits. Colon cancer and rectal cancer or colorectal cancer in general in the early stages of the disease, may not show symptoms or are barely noticeable. Colorectal cancer symptoms will most often not develop until the disease has progressed to stage 2 or beyond. Regular screening tests for colon or rectal cancer, especially colonoscopy, are recommended as part of a regular checkup for people aged 50 years or younger who are at high risk due to a family history of the disease or other cancers. Diet and colonoscopy as an early screening method play an important role in the prevention of colorectal cancer.

Electroacupuncture at Zusanli regulates the pathological phenotype of inflammatory bowel disease by modulating the NLRP3 inflammasome pathway

BACKGROUND

This study sought to explore the effect of electroacupuncture (EA) intervention at Zusanli (ST36) acupoint on modulating the NLRP3 inflammasome pathway for treating inflammatory bowel disease (IBD).

METHODS

C57BL/6 mice were administrated with 3% dextran sulfate sodium (DSS) to construct the IBD model. DSS mice were then administrated with EA (10 Hz, 1.5 mA) at ST36 for 7 days or intragastric administration of sulfasalazine (SASP) each day during the entire course. The control group animals were administered with distilled water. Then, partial least squares discriminant analysis revealed differences in the relative content of metabolites. The pathological changes of colon and spleen tissues were observed by H&E and immunohistochemistry (IHC) staining. qPCR determined the mRNA expression levels, while ELISA and western blot analysis determined the protein expression.

RESULTS

Compared with the control groups, DSS-induced decreases of body weight were reversed after EA stimulation at ST36 or SASP treatment. The DAI of DSS mice was significantly higher relative to the control groups, whereas the DAI of DSS mice were decreased after EA stimulation at ST36 or SASP treatment. The intestinal weight/length ratio increased significantly in DSS groups; however, EA at ST36 significantly improved the macroscopic/microscopic characteristics and the weight and length of the colon. EA reversed inflammation and leukocyte infiltration and normalized the elevated levels of IL-1β, IL-18, and NLRP3. Furthermore, EA improved the expression levels of ZO-1, occludin, and claudin 1, exhibiting normalization of the colon's tight junctions.

CONCLUSIONS

EA at Zusanli acupoint of colon tissue significantly improved the pathological phenotype, showing a therapeutic effect on IBD.

Release profile of amino acids encapsulated in solid lipid particles during in vitro oro-gastrointestinal digestion

Some amino acids are known to mediate immune responses through gut microbiota metabolism in both humans and monogastric animals. However, through the diet, most free amino acids are absorbed in the small intestine and only a small quantity reaches the microbiota-rich colon. To enhance microbial metabolism of amino acids and their potential health benefits, encapsulation strategies are developed for their protection and delivery to the colon. So far, the main encapsulation systems for amino acids are based on solid lipid particles, but their fate within the digestive tract has never been fully clarified. In this study, we investigated the release of various amino acids (branched-chain amino acid mixture, or lysine, or tryptophan) loaded in solid lipid particles during in vitro oro-gastrointestinal digestion mimicking the piglet. The loaded solid lipid particles were fully characterized for their composition, thermal behavior, molecular structure, crystalline state, surface morphology, and particle size distribution. Moreover, we investigated the effect of particle size by sieving solid lipid particles into two non-overlapping size fractions. We found that amino acid release was high during the gastric phase of digestion, mainly controlled by physical parameters, namely particle size and crystalline state including surface morphology. Large particle size and/or smooth ordered particle indeed led to slower and lower release. Although lipid hydrolysis was significant during the intestinal phase of digestion, the impact of the crystalline state and surface morphology was also observed in the absence of enzymes, pointing to a dominant water/solute diffusion mechanism through these porous solid lipid particles.

Lactiplantibacillus argentoratensis AGMB00912 alleviates salmonellosis and modulates gut microbiota in weaned piglets: a pilot study

This study aimed to evaluate the efficacy of Lactiplantibacillus argentoratensis AGMB00912 (LA) in reducing Salmonella Typhimurium infection in weaned piglets. The investigation focused on the influence of LA on the gut microbiota composition, growth performance, and Salmonella fecal shedding. The results indicated that LA supplementation significantly improved average daily gain and reduced the prevalence and severity of diarrhea. Fecal analysis revealed reduced Salmonella shedding in the LA-supplemented group. Furthermore, LA notably altered the composition of the gut microbiota, increasing the levels of beneficial Bacillus and decreasing those of harmful Proteobacteria and Spirochaetes. Histopathological examination showed less intestinal damage in LA-treated piglets than in the controls. The study also observed that LA affected metabolic functions related to carbohydrate, amino acid, and fatty acid metabolism, thereby enhancing gut health and resilience against infection. Short-chain fatty acid concentrations in the feces were higher in the LA group, suggesting improved gut microbial activity. LA supplementation enriched the population of beneficial bacteria, including Streptococcus, Clostridium, and Bifidobacterium, while reducing the number of harmful bacteria, such as Escherichia and Campylobacter. These findings indicate the potential of LA as a probiotic alternative for swine nutrition, offering protective effects to the gut microbiota against Salmonella infection.

Evaluation of the Crosstalk Between the Host Mycobiome and Bacteriome in Patients with Chronic Pancreatitis

The human microbiome is a diverse consortium of microbial kingdoms that play pivotal roles in host health and diseases. We previously reported a dysbiotic bacteriome in chronic pancreatitis patients with diabetes (CPD) compared with patients with it's nondiabetic (CPND) phenotype. In this study, we extended our exploration to elucidate the intricate interactions between the mycobiome, bacteriome, and hosts' plasma metabolome with the disease phenotypes. A total of 25 participants (CPD, n = 7; CPND, n = 10; healthy control, n = 8) were recruited for the study. We observed elevated species richness in both the bacterial and fungal profiles within the CP diabetic cohort compared to the nondiabetic CP phenotype and healthy control cohorts. Notably, the CP group displayed heterogeneous fungal diversity, with only 40% of the CP nondiabetic patients and 20% of the CP diabetic patients exhibiting common core gut fungal profiles. Specific microbial taxa alterations were identified, including a reduction in Bifidobacterium adolescentis and an increase in the prevalence of Aspergillus penicilloides and Klebsiella sp. in the disease groups. In silico analysis revealed the enrichment of pathways related to lipopolysaccharide (LPS), apoptosis, and peptidase, as well as reduced counts of the genes responsible for carbohydrate metabolism in the CP groups. Additionally, distinct plasma metabolome signatures were observed, with CPD group exhibiting higher concentrations of sugars and glycerolipids, while the CPND cohort displayed elevated levels of amino acids in their blood. The fatty acid-binding protein (FABP) concentration was notably greater in the CPD group than in the HC group (4.220 vs. 1.10 ng/ml, p = 0.04). Furthermore, compared with healthy controls, disease groups exhibited fewer correlations between key fungal taxa (Aspergillus sp., Candida sp.) and bacterial taxa (Prevotella copri, Bifidobacteria sp., Rumminococcaceae). Our study unveils, for the first time, a dysbiotic mycobiome and emphasizes unique host bacterial-mycobial interactions in CP patient with diabetes, potentially influencing disease severity. These findings provide crucial insights for future mechanistic studies aiming to unravel the determinants of disease severity in this complex clinical context.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-024-01207-8.

Resistance role of Lactobacillus sp. and Lactococcus sp. to copper ions in healthy children's intestinal microorganisms

Heavy metal exposure is closely associated with gut microbe function and tolerance. However, intestinal microbe responses in children to different copper ion (Cu2+) concentrations have not yet been clarified. Here, in vitro cultivation systems were established for fecal microbe control and Cu2+-treated groups in healthy children. 16S rDNA high-throughput sequencing, meta-transcriptomics and metabolomics were used here to identify toxicity resistance mechanisms at microbiome levels. The results showed that Lactobacillus sp. and Lactococcus sp. exerted protective effects against Cu2+ toxicity, but these effects were limited by Cu2+ concentration. When the Cu2+ concentration was ≥ 4 mg/L, the abundance of Lactobacillus sp. and Lactococcus sp. significantly decreased, and the pathways of antioxidant activity and detoxification processes were enriched at 2 mg/L Cu2+, and beneficial metabolites accumulated. However, at high concentrations of Cu2+ (≥4 mg/L), the abundance of potential pathogen increased, and was accompanied by a downregulation of genes in metabolism and detoxification pathways, which meant that the balance of gut microbiota was disrupted and toxicity resistance decreased. From these observations, we identified some probiotics that are tolerant to heavy metal Cu2+, and warn that only when the concentration limit of Cu2+ in food is 2 mg/L, then a balanced gut microbiota can be guaranteed in children, thereby providing protection for their health.

Interaction between Dietary Lactoferrin and Gut Microbiota in Host Health

The gut microbiota are known to play an important role in host health and disease. Alterations in the gut microbiota composition can disrupt the stability of the gut ecosystem, which may result in noncommunicable chronic diseases (NCCDs). Remodeling the gut microbiota through personalized nutrition is a novel therapeutic avenue for both disease control and prevention. However, whether there are commonly used gut microbiota-targeted diets and how gut microbiota-diet interactions combat NCCDs and improve health remain questions to be addressed. Lactoferrin (LF), which is broadly used in dietary supplements, acts not only as an antimicrobial in the defense against enteropathogenic bacteria but also as a prebiotic to propagate certain probiotics. Thus, LF-induced gut microbiota alterations can be harnessed to induce changes in host physiology, and the underpinnings of their relationships and mechanisms are beginning to unravel in studies involving humans and animal models.

Different fat-to-fiber ratios by changing wheat inclusion level impact energy metabolism and microbial structure of broilers

Introduction

Dietary nutrient content is crucial for energy metabolism and development of gut microbiota. Herein, this study aimed to explore the effects of fat-to-fiber ratios on nutrient transporter, energy metabolism and gut microbiota when ingredients composition was altered.

Methods

A total of 240 as-hatched broiler chickens were randomly assigned into three groups including low fat-high dietary fiber (LF-HD), medium fat-medium dietary fiber (MF-MD) and high fat-low dietary fiber (HF-LD), with diets being iso-protein, and broilers were offered the same commercial diets from 21 to 42 d. The data were analyzed using one-way ANOVA of SPSS.

Results and Discussion

Results showed that HF-LD diet significantly increased glucose content and decreased triglyceride in serum of broilers (p < 0.05). The mRNA abundance of jejunal gene involved in glucose transporter and tricarboxylic acid (TCA) cycle was significantly increased in broilers fed with HF-LD diets. Compared with LF-HD, HF-LD had a lower abundance of Anaerofilum and CHKCI001, and an increased proportion of beneficial bacteria such as Alistipes, Catenibacillus, Intestinimonas, Lactobacillus, and Peptococcus (p < 0.05). Functional prediction of these microbial changes indicated that HF-LD diet drove caecal microbiota to participate in carbohydrate metabolism and TCA cycle (p < 0.05). Dietary HF-LD-induced microbiota changes were positively correlated with growth performance of broilers (p < 0.05). Therefore, HF-LD diet increased glucose transporters and energy metabolism in intestine and shaped microbial structure and metabolic pathways, which may benefit the growth performance of broilers.

Isocaloric diets with varying protein levels affected energy metabolism in young adult Sprague-Dawley rats via modifying the gut microbes: A lipid imbalance was brought on by a diet with a particularly high protein content

Protein is the most important macro-nutrient when it comes to maximizing health, body composition, muscle growth, and recovery of body tissue. In recent years, it has been found that protein also plays an important role in metabolism and gut microbiota. This study was performed to investigate the effects of an isocaloric diet with different crude protein contents on the energy metabolism of Sprague-Dawley (SD) rats. Results revealed that compared with the 20% crude protein (CP; control) diet, the 38% CP diet improved serum parameters that are associated with dyslipidemia and glucose metabolic disorders in SD rats, whereas the 50% CP diet increased liver injury indicators and fatty acid synthesis-related genes and protein expression in the liver. Compared with the control diet, the 14% CP diet increased the abundance of colonic short-chain fatty acid-producing bacteria (Lachnospiraceae_NK4A136_group and Ruminiclostridium_9) and promoted colonic microbial cysteine and methionine metabolism, the 38% CP diet up-regulated colonic microbial lysine biosynthesis and degradation pathways, and the 50% CP diet down-regulated colonic mucosal cholesterol metabolism. Furthermore, the increase of multiple colonic enteropathogenic bacteria in the 50% CP group was associated with higher palmitic acid and stearic acid concentrations in the colonic microbes and lower cholesterol and arachidonic acid concentrations in the colonic mucosa. These findings revealed that the 14% CP and 38% CP diets improved rats' energy metabolism, while the 50% CP diet was accompanied by lipid metabolism imbalances and an increase in the abundance of multiple enteropathogenic bacteria.

Swine Gastrointestinal Microbiota and the Effects of Dietary Amino Acids on Its Composition and Metabolism

Many researchers consider gut microbiota (trillions of microorganisms) an endogenous organ of its animal host, which confers a vast genetic diversity in providing the host with essential biological functions. Particularly, the gut microbiota regulates not only gut tissue structure but also gut health and gut functionality. This paper first summarized those common bacterial species (dominated by the Firmicutes, Bacteroidota, and Proteobacteria phyla) in swine gut and then briefly discussed their roles in swine nutrition and health, which include roles in nutrient metabolism, pathogen exclusion, and immunity modulation. Secondly, the current knowledge on how dietary nutrients and feed additives affect the gut bacterial composition and nutrient metabolism in pigs was discussed. Finally, how dietary amino acids affect the relative abundances and metabolism of bacteria in the swine gut was reviewed. Tryptophan supplementation promotes the growth of beneficial bacteria and suppresses pathogens, while arginine metabolism affects nitrogen recycling, impacting gut immune response and health. Glutamate and glutamine supplementations elevate the levels of beneficial bacteria and mitigate pathogenic ones. It was concluded that nutritional strategies to manipulate gut microbial ecosystems are useful measures to optimize gut health and gut functions. For example, providing pigs with nutrients that promote the growth of Lactobacillus and Bifidobacterium can lead to better gut health and growth performance, especially when dietary protein is limited. Further research to establish the mechanistic cause-and-effect relationships between amino acids and the dynamics of gut microbiota will allow swine producers to reap the greatest return on their feed investment.

Comparison of Intestinal Microbiota of Blue Fox before and after Weaning

Intestinal flora plays an important role in maintaining the internal stability and health of the intestine. Currently, intestinal microbes are considered an important "organ" but are mostly ignored by people. This study evaluated the flora structure of each intestinal segment of blue foxes pre-weaning and explored the differences between the fecal flora and intestinal flora structure of each segment after weaning. Samples of intestinal contents from three blue foxes at 45 days of age (before weaning) and intestinal contents and feces samples from at 80 days (after weaning) were collected for 16s rRNA flora analysis. The species and distribution characteristics of microorganisms in different intestinal segments of blue foxes before and after weaning were different. Except for the rectum, the dominant flora of each intestinal segment of blue fox changed significantly after experiencing weaning, and the fecal flora structure of young fox at the weaning stage did not represent the whole intestinal flora structure but was highly similar to that of the colon and rectum. To sum up, the intestinal flora of blue foxes changed systematically before and after weaning. When performing non-invasive experiments, the microflora structure of the colon and rectum of blue foxes can be predicted by collecting fecal samples.

The impact of gut microbiome enterotypes on ulcerative colitis: identifying key bacterial species and revealing species co-occurrence networks using machine learning

Ulcerative colitis (UC) is a chronic inflammatory intestinal disease affecting the colon and rectum, with its pathogenesis attributed to genetic background, environmental factors, and gut microbes. This study aimed to investigate the role of enterotypes in UC by conducting a hierarchical analysis, determining differential bacteria using machine learning, and performing Species Co-occurrence Network (SCN) analysis. Fecal bacterial data were collected from UC patients, and a 16S rRNA metagenomic analysis was performed using the QIIME2 bioinformatics pipeline. Enterotype clustering was conducted at the family level, and deep neural network (DNN) classification models were trained for UC and healthy controls (HC) in each enterotype. Results from eleven 16S rRNA gut microbiome datasets revealed three enterotypes: Bacteroidaceae (ET-B), Lachnospiraceae (ET-L), and Clostridiaceae (ET-C). Ruminococcus (R. gnavus) abundance was significantly higher in UC subjects with ET-B and ET-C than in those with ET-L. R. gnavus also showed a positive correlation with Clostridia in UC SCN for ET-B and ET-C subjects, with a higher correlation in ET-C subjects. Conversely, Odoribacter (O.) splanchnicus and Bacteroides (B.) uniformis exhibited a positive correlation with tryptophan metabolism and AMP-activated protein kinase (AMPK) signaling pathways, while R. gnavus showed a negative correlation. In vitro co-culture experiments with Clostridium (C.) difficile demonstrated that fecal microbiota from ET-B subjects had a higher abundance of C. difficile than ET-L subjects. In conclusion, the ET-B enterotype predisposes individuals to UC, with R. gnavus as a potential risk factor and O. splanchnicus and B. uniformis as protective bacteria, and those with UC may have ultimately become ET-C.

The roles of short-chain fatty acids derived from colonic bacteria fermentation of non-digestible carbohydrates and exogenous forms in ameliorating intestinal mucosal immunity of young ruminants

Short-chain fatty acids (SCFA) are a class of organic fatty acids that consist of 1 to 6 carbons in length. They are primary end-products which arise from non-digestible carbohydrates (NDC) fermentation of colonic bacteria. They are the fundamental energy sources for post-weaning ruminants. SCFA represent the major carbon flux of diet through the gut microbiota to the host. They also play a vital role in regulating cell expansion and gene expression of the gastrointestinal tract (GIT). Recently, remarkable progresses have been made in understanding the immunomodulatory effects of SCFA and their interactions with the host. The processes involved in this study encompassed inflammasome activation, proliferation of lymphocytes, and maturation of intestinal mucosal immunity maturation. It is important to note that the establishment and maturation of intestinal mucosal immune system are intricately connected to the barrier function of intestinal epithelial cells (IEC) and the homeostasis of gut microbiota. Thus, insights into the role of SCFA in enteric mucosal immunoreaction of calves will enhance our understanding of their various regulatory functions. This review aims to analyze recent evidence on the role of SCFA as essential signaling molecules between gut microbiota and animal health. Additionally, we provide a summary of current literature on SCFA in intestinal mucosal immune responses of dairy calves.

Rapid intestinal and systemic metabolic reprogramming in an immunosuppressed environment

Intrinsic metabolism shapes the immune environment associated with immune suppression and tolerance in settings such as organ transplantation and cancer. However, little is known about the metabolic activities in an immunosuppressive environment. In this study, we employed metagenomic, metabolomic, and immunological approaches to profile the early effects of the immunosuppressant drug tacrolimus, antibiotics, or both in gut lumen and circulation using a murine model. Tacrolimus induced rapid and profound alterations in metabolic activities within two days of treatment, prior to alterations in gut microbiota composition and structure. The metabolic profile and gut microbiome after seven days of treatment was distinct from that after two days of treatment, indicating continuous drug effects on both gut microbial ecosystem and host metabolism. The most affected taxonomic groups are Clostriales and Verrucomicrobiae (i.e., Akkermansia muciniphila), and the most affected metabolic pathways included a group of interconnected amino acids, bile acid conjugation, glucose homeostasis, and energy production. Highly correlated metabolic changes were observed between lumen and serum metabolism, supporting their significant interactions. Despite a small sample size, this study explored the largely uncharacterized microbial and metabolic events in an immunosuppressed environment and demonstrated that early changes in metabolic activities can have significant implications that may serve as antecedent biomarkers of immune activation or quiescence. To understand the intricate relationships among gut microbiome, metabolic activities, and immune cells in an immune suppressed environment is a prerequisite for developing strategies to monitor and optimize alloimmune responses that determine transplant outcomes.

Paneth cells in farm animals: current status and future direction

A healthy intestine plays an important role in the growth and development of farm animals. In small intestine, Paneth cells are well known for their regulation of intestinal microbiota and intestinal stem cells (ISCs). Although there has been a lot of studies and reviews on human and murine Paneth cells under intestinal homeostasis or disorders, little is known about Paneth cells in farm animals. Most farm animals possess Paneth cells in their small intestine, as identified by various staining methods, and Paneth cells of various livestock species exhibit noticeable differences in cell shape, granule number, and intestinal distribution. Paneth cells in farm animals and their antimicrobial peptides (AMPs) are susceptible to multiple factors such as dietary nutrients and intestinal infection. Thus, the comprehensive understanding of Paneth cells in different livestock species will contribute to the improvement of intestinal health. This review first summarizes the current status of Paneth cells in pig, cattle, sheep, horse, chicken and rabbit, and points out future directions for the investigation of Paneth cells in the reviewed animals.

Improving mesophilic anaerobic digestion of food waste by side-stream thermophilic reactor: Activation of methanogenic, key enzymes and metabolism

Anaerobic digestion (AD) is a favorable way to convert organic pollutants, such as food waste (FW), into clean energy through microbial action. This work adopted a side-stream thermophilic anaerobic digestion (STA) strategy to improve a digestive system's efficiency and stability. Results showed that the STA strategy brought higher methane production as well as higher system stability. It quickly adapted to thermal stimulation and increased the specific methane production from 359 mL CH₄/g·VS to 439 mL CH₄/g·VS, which was also higher than 317 mL CH₄/g·VS from single-stage thermophilic anaerobic digestion. Further exploration of the mechanism of STA using metagenomic and metaproteomic analysis revealed enhanced activity of key enzymes. The main metabolic pathway was up-regulated, while the dominant bacteria were concentrated, and the multifunctional Methanosarcina was enriched. These results indicate that STA optimized organic metabolism patterns, comprehensively promoted methane production pathways, and formed various energy conservation mechanisms. Further, the system's limited heating avoided adverse effects from thermal stimulation, and activated enzyme activity and heat shock proteins through circulating slurries, which improved the metabolic process, showing great application potential.

Impacts of microgravity on amino acid metabolism during spaceflight

Spaceflight exerts an extreme and unique influence on human physiology as astronauts are subjected to long-term or short-term exposure to microgravity. During spaceflight, a multitude of physiological changes, including the loss of skeletal muscle mass, bone resorption, oxidative stress, and impaired blood flow, occur, which can affect astronaut health and the likelihood of mission success. In vivo and in vitro metabolite studies suggest that amino acids are among the most affected nutrients and metabolites by microgravity (a weightless condition due to very weak gravitational forces). Moreover, exposure to microgravity alters gut microbial composition, immune function, musculoskeletal health, and consequently amino acid metabolism. Appropriate knowledge of daily protein consumption, with a focus on specific functional amino acids, may offer insight into potential combative and/or therapeutic effects of amino acid consumption in astronauts and space travelers. This will further aid in the successful development of long-term manned space mission and permanent space habitats.

Metabolite profiling of human-originated Lachnospiraceae at the strain level

The human gastrointestinal (GI) tract harbors diverse microbes, and the family Lachnospiraceae is one of the most abundant and widely occurring bacterial groups in the human GI tract. Beneficial and adverse effects of the Lachnospiraceae on host health were reported, but the diversities at species/strain levels as well as their metabolites of Lachnospiraceae have been, so far, not well documented. In the present study, we report on the collection of 77 human-originated Lachnospiraceae species (please refer hLchsp, https://hgmb.nmdc.cn/subject/lachnospiraceae) and the in vitro metabolite profiles of 110 Lachnospiraceae strains (https://hgmb.nmdc.cn/subject/lachnospiraceae/metabolites). The Lachnospiraceae strains in hLchsp produced 242 metabolites of 17 categories. The larger categories were alcohols (89), ketones (35), pyrazines (29), short (C2-C5), and long (C > 5) chain acids (31), phenols (14), aldehydes (14), and other 30 compounds. Among them, 22 metabolites were aromatic compounds. The well-known beneficial gut microbial metabolite, butyric acid, was generally produced by many Lachnospiraceae strains, and Agathobacter rectalis strain Lach-101 and Coprococcus comes strain NSJ-173 were the top 2 butyric acid producers, as 331.5 and 310.9 mg/L of butyric acids were produced in vitro, respectively. Further analysis of the publicly available cohort-based volatile-metabolomic data sets of human feces revealed that over 30% of the prevailing volatile metabolites were covered by Lachnospiraceae metabolites identified in this study. This study provides Lachnospiraceae strain resources together with their metabolic profiles for future studies on host-microbe interactions and developments of novel probiotics or biotherapies.

Low fish meal diet supplemented with probiotics ameliorates intestinal barrier and immunological function of Macrobrachium rosenbergii via the targeted modulation of gut microbes and derived secondary metabolites

The unsuitable substitution ratio of fish meal by plant protein will reshape the intestinal microbial composition and intestine immunity. However, previous studies were mostly limited to investigating how different feed or probiotics characterized the microbial composition but ignored the biological interactions between bacteria and host physiology through secondary metabolites. Therefore, this study integrates the apparent indicators monitoring, 16S rDNA sequencing, and metabonomics to systematically investigate the effects of cottonseed protein concentrate (CPC) substitution of fish meal and Bacillus coagulans intervention on gut microbes, secondary metabolites, and intestinal immunity of Macrobrachium rosenbergii. Prawns were fed with three diets for 70 days: HF diets contained 25% fish meal, CPC in LF diets were replaced with 10% fish meal, and LF diets supplemented with 2 × 108 CFU/g diet B. coagulans were designated as BC diets. Results showed that CPC substitution induced a significant decrease in digestive enzyme activities (trypsin and lipase) and gut barrier protein PT-1 expression and a significant increase in γ-GT enzyme activity and inflammatory-related factors (Relish and Toll) expression. B. coagulans treatment mitigated the negative changes of the above indicators. Meanwhile, it significantly improved the expression levels of the barrier factor PT-1, the reparative cytokine IL-22, and Cu/Zn-SOD. CPC substitution resulted in a remarkable downregulated abundance of Firmicutes phyla, Flavobacterium spp., and Bacillus spp. B. coagulans treatment induced the callback of Firmicutes abundance and improved the relative abundance of Sphingomonas, Bacillus, and Ralstonia. Functional prediction indicated that CPC substitution resulted in elevated potential pathogenicity of microbial flora, and B. coagulans reduces the pathogenesis risk. Pearson's correlation analysis established a significant positive correlation between differential genera (Sphingomonas, Bacillus, and Ralstonia) and secondary metabolites (including sphingosine, dehydrophytosphingosine, amino acid metabolites, etc.). Meanwhile, the latter were significantly associated with intestinal immunoregulation-related genes (Cu/Zn-SOD, IL-22, PT-1, Toll, and Relish). This study indicated that B. coagulans could mediate specific gut microbes and the combined action of multiple functional secondary metabolites to affect intestinal barrier function, digestion, and inflammation. Our study revealed the decisive role of gut microbes and derived secondary metabolites in the model of dietary composition-induced intestinal injury and probiotic treatment from a new perspective.

Examining the effects of Salmonella phage on the caecal microbiota and metabolome features in Salmonella-free broilers

Bacteriophages selectively infect and kill their target bacterial host, being a promising approach to controlling zoonotic bacteria in poultry production. To ensure confidence in its use, fundamental questions of safety and toxicity monitoring of phage therapy should be raised. Due to its high specificity, a minimal impact on the gut ecology is expected; however, more in-depth research into key parameters that influence the success of phage interventions has been needed to reach a consensus on the impact of bacteriophage therapy in the gut. In this context, this study aimed to investigate the interaction of phages with animals; more specifically, we compared the caecum microbiome and metabolome after a Salmonella phage challenge in Salmonella-free broilers, evaluating the role of the phage administration route. To this end, we employed 45 caecum content samples from a previous study where Salmonella phages were administered via drinking water or feed for 24 h from 4, 5 to 6-weeks-old broilers. High-throughput 16S rRNA gene sequencing showed a high level of similarity (beta diversity) but revealed a significant change in alpha diversity between broilers with Salmonella-phage administered in the drinking water and control. Our results showed that the phages affected only a few genera of the microbiota's structure, regardless of the administration route. Among these, we found a significant increase in Streptococcus and Sellimonas in the drinking water and Lactobacillus, Anaeroplasma and Clostridia_vadinBB60_group in the feed. Nevertheless, the LC-HRMS-based metabolomics analyses revealed that despite few genera were significantly affected, a substantial number of metabolites, especially in the phage administered in the drinking water were significantly altered (64 and 14 in the drinking water and feed groups, respectively). Overall, our study shows that preventive therapy with bacteriophages minimally alters the caecal microbiota but significantly impacts their metabolites, regardless of the route of administration.

Interactions between gut microbiota and Parkinson's disease: The role of microbiota-derived amino acid metabolism

Non-motor symptoms (NMS) of Parkinson's disease (PD), such as constipation, sleep disorders, and olfactory deficits, may emerge up to 20 years earlier than motor symptoms. A series of evidence indicates that the pathology of PD may occur from the gastrointestinal tract to the brain. Numerous studies support that the gut microbiota communicates with the brain through the immune system, special amino acid metabolism, and the nervous system in PD. Recently, there is growing recognition that the gut microbiota plays a vital role in the modulation of multiple neurochemical pathways via the “gut microbiota-brain axis” (GMBA). Many gut microbiota metabolites, such as fatty acids, amino acids, and bile acids, convey signaling functions as they mediate the crosstalk between gut microbiota and host physiology. Amino acids' abundance and species alteration, including glutamate and tryptophan, may disturb the signaling transmission between nerve cells and disrupt the normal basal ganglia function in PD. Specific amino acids and their receptors are considered new potential targets for ameliorating PD. The present study aimed to systematically summarize all available evidence on the gut microbiota-derived amino acid metabolism alterations associated with PD.

The role of the gut microbiota in health and cardiovascular diseases

The gut microbiota is critical to human health, such as digesting nutrients, forming the intestinal epithelial barrier, regulating immune function, producing vitamins and hormones, and producing metabolites to interact with the host. Meanwhile, increasing evidence indicates that the gut microbiota has a strong correlation with the occurrence, progression and treatment of cardiovascular diseases (CVDs). In patients with CVDs and corresponding risk factors, the composition and ratio of gut microbiota have significant differences compared with their healthy counterparts. Therefore, gut microbiota dysbiosis, gut microbiota-generated metabolites, and the related signaling pathway may serve as explanations for some of the mechanisms about the occurrence and development of CVDs. Several studies have also demonstrated that many traditional and latest therapeutic treatments of CVDs are associated with the gut microbiota and its generated metabolites and related signaling pathways. Given that information, we summarized the latest advances in the current research regarding the effect of gut microbiota on health, the main cardiovascular risk factors, and CVDs, highlighted the roles and mechanisms of several metabolites, and introduced corresponding promising treatments for CVDs regarding the gut microbiota. Therefore, this review mainly focuses on exploring the role of gut microbiota related metabolites and their therapeutic potential in CVDs, which may eventually provide better solutions in the development of therapeutic treatment as well as the prevention of CVDs.

Melatonin mitigates aflatoxin B1-induced liver injury via modulation of gut microbiota/intestinal FXR/liver TLR4 signaling axis in mice

Aflatoxin B1 (AFB1) is a widespread contaminant in foods and feedstuffs, and its target organ is the liver. Melatonin (MT) has been shown to alleviate inflammation in organs and remodel gut microbiota in animals and humans. However, the underlying mechanism by which MT alleviates AFB1-induced liver injury remains unclear. In the present study, MT pretreatment markedly increased the expression of intestinal tight junction proteins (ZO-1, Occludin, and Claudin-1), decreased intestinal permeability, reduced production of gut-derived Lipopolysaccharide (LPS) and remodeled gut microbiota, ultimately alleviated AFB1-induced liver injury in mice. Interestingly, MT pretreatment failed to exert beneficial effects on the intestine and liver in antibiotic-treated mice. Meanwhile, MT pretreatment significantly increased the farnesoid X receptor (FXR) protein expression of ileum, and decreased the TLR4/NF-κB signaling pathway-related messenger RNA (mRNA) and proteins (TLR4, MyD88, p-p65, and p-IκBα) expression in livers of AFB1-exposed mice. Subsequently, pretreatment by Gly-β-MCA, an intestine-selective FXR inhibitor, blocked the alleviating effect of MT on liver injury through increasing the liver-specific expression of TLR4/NF-κB signaling pathway-related mRNA and proteins (TLR4, MyD88, p-p65, and p-IκBα). In conclusion, MT pretreatment ameliorated AFB1-induced liver injury and the potential mechanism may be related to regulate gut microbiota/intestinal FXR/liver TLR4 signaling axis, which provides a strong evidence for the protection of gut-derived liver inflammation.

Influence of Foods and Nutrition on the Gut Microbiome and Implications for Intestinal Health

Food components in our diet provide not only necessary nutrients to our body but also substrates for the mutualistic microbial flora in our gastrointestinal tract, termed the gut microbiome. Undigested food components are metabolized to a diverse array of metabolites. Thus, what we eat shapes the structure, composition, and function of the gut microbiome, which interacts with the gut epithelium and mucosal immune system and maintains intestinal homeostasis in a healthy state. Alterations of the gut microbiome are implicated in many diseases, such as inflammatory bowel disease (IBD). There is growing interest in nutritional therapy to target the gut microbiome in IBD. Investigations into dietary effects on the composition changes in the gut microbiome flourished in recent years, but few focused on gut physiology. This review summarizes the current knowledge regarding the impacts of major food components and their metabolites on the gut and health consequences, specifically within the GI tract. Additionally, the influence of the diet on the gut microbiome-host immune system interaction in IBD is also discussed. Understanding the influence of the diet on the interaction of the gut microbiome and the host immune system will be useful in developing nutritional strategies to maintain gut health and restore a healthy microbiome in IBD.

Effects of Marine Bioactive Compounds on Gut Ecology Based on In Vitro Digestion and Colonic Fermentation Models

Digestion and the absorption of food compounds are necessary steps before nutrients can exert a role in human health. The absorption and utilization of nutrients in the diet is an extremely complex dynamic process. Accurately grasping the digestion and absorption mechanisms of different nutrients or bioactive compounds can provide a better understanding regarding the relationship between health and nutrition. Several in vitro models for simulating human gastrointestinal digestion and colonic fermentation have been established to obtain more accurate data for further understanding of the metabolism of dietary components. Marine media is rich in a wide variety of nutrients that are essential for humans and is gaining increased attention as a research topic. This review summarizes some of the most explored in vitro digestion and colonic fermentation models. It also summarizes the research progress on the digestion and absorption of nutrients and bioactive compounds from marine substrates when subjected to these in vitro models. Additionally, an overview of the changes imparted by the digestion process on these bioactive compounds is provided, in order to support those marine resources that can be utilized for developing new healthy foods.

Dietary Component-Induced Inflammation and Its Amelioration by Prebiotics, Probiotics, and Synbiotics

A balanced diet with many dietary components maintains immune homeostasis directly by interacting with innate and adaptive immune components or indirectly through gut microbiota and their metabolites. Dietary components may inhibit pro-inflammatory mediators and promote anti-inflammatory functions or vice versa. Western diets with imbalanced dietary components skew the immune balance toward pro-inflammation and induce intestinal inflammation, consequently leading to many intestinal and systemic inflammatory diseases like ulcerative colitis, Crohn's disease, irritable bowel syndrome, cardiovascular problems, obesity, and diabetes. The dietary component-induced inflammation is usually chronic in nature and frequently caused or accompanied by alterations in gut microbiota. Therefore, microbiome-targeted therapies such as probiotics, prebiotics and synbiotics hold great potentials to amend immune dysregulation and gut dysbiosis, preventing and treating intestinal and systemic inflammatory diseases. Probiotics, prebiotics and synbioitcs are progressively being added to foods and beverages, with claims of health benefits. However, the underlining mechanisms of these interventions for preventing and treating dietary component-induced inflammation are still not very clear. In addition, possibly ineffective or negative consequences of some probiotics, prebiotics and synbiotics call for stringent testing and regulation. Here, we will first briefly review inflammation, in terms of its types and the relationship between different dietary components and immune responses. Then, we focus on current knowledge about the direct and indirect effects of probiotics, prebiotics and synbiotics on intestinal and systemic inflammation. Understanding how probiotics, prebiotics and synbiotics modulate the immune system and gut microbiota will improve our strategies for preventing and treating dietary component-induced intestinal inflammation and inflammatory diseases.

Effect of Various Preterm Infant Milk Formulas on NEC-Like Gut Injury in Mice

Formula feeding is an important risk factor for the development of necrotizing enterocolitis in preterm infants. The potential harmful effects of different preterm formulas on the developing intestinal tract remain incompletely understood. Here we demonstrate that feeding newborn mouse pups with various preterm formulas resulted in differing effects on intestinal inflammation, apoptosis, and activation of the pro-inflammatory transcription factor NFκB. 16S rRNA sequencing revealed that each preterm formula resulted in significant gut microbial alterations that were different from dam-fed controls. Formula feeding with EleCare and Similac Special Care caused greater intestinal injury compared to NeoSure. Pre-treatment with Lactobacillus rhamnosus GG ameliorated severity of intestinal injury from EleCare and Similac Special Care. Our findings indicate that not all preterm formulas are the same, and different formulations can have varying effects on intestinal inflammation, apoptosis, and microbiome composition.

Metabolomics: The Key to Unraveling the Role of the Microbiome in Visceral Pain Neurotransmission

Inflammatory bowel disease (IBD), comprising Crohn's disease and Ulcerative colitis, is a relapsing and remitting disease of the gastrointestinal tract, presenting with chronic inflammation, ulceration, gastrointestinal bleeding, and abdominal pain. Up to 80% of patients suffering from IBD experience acute pain, which dissipates when the underlying inflammation and tissue damage resolves. However, despite achieving endoscopic remission with no signs of ongoing intestinal inflammation or damage, 30-50% of IBD patients in remission experience chronic abdominal pain, suggesting altered sensory neuronal processing in this disorder. Furthermore, effective treatment for chronic pain is limited such that 5-25% of IBD outpatients are treated with narcotics, with associated morbidity and mortality. IBD patients commonly present with substantial alterations to the microbial community structure within the gastrointestinal tract, known as dysbiosis. The same is also true in irritable bowel syndrome (IBS), a chronic disorder characterized by altered bowel habits and abdominal pain, in the absence of inflammation. An emerging body of literature suggests that the gut microbiome plays an important role in visceral hypersensitivity. Specific microbial metabolites have an intimate relationship with host receptors that are highly expressed on host cell and neurons, suggesting that microbial metabolites play a key role in visceral hypersensitivity. In this review, we will discuss the techniques used to analysis the metabolome, current potential metabolite targets for visceral hypersensitivity, and discuss the current literature that evaluates the role of the post-inflammatory microbiota and metabolites in visceral hypersensitivity.

Experimental Investigation on the Bioprotective Role of Trehalose on Glutamine Solutions by Infrared Spectroscopy

Glutamine plays a significant role in several basic metabolic processes and is an important regulator of heat shock protein response. The present work is focused on the analysis of the thermal response of aqueous solutions of Glutamine and aqueous solutions of Glutamine in the presence of Trehalose by means of infrared absorption technique. The performed study shows how in the case of a multicomponent system, characterized by a huge number of spectral contributions whose assignment are questionable, the Spectral Distance (SD) and the Cross Wavelet Correlation (XWT) approaches are able to furnish explanatory parameters that can characterize the variations in the spectra behaviour, which is an efficient tool for quantitative comparisons. With this purpose, the analysis has been performed by evaluating the SD and the XWT parameters for the whole investigated spectral range, i.e., 4000–400 cm⁻¹, for scans collected as a function of temperature in the range 20 °C ÷ 60 °C both for Glutamine/Water compounds and for Glutamine /Water/Trehalose mixtures. By means of these analyses, it is found that in aqueous solutions of Glutamine, with respect to aqueous solutions of Glutamine in the presence of Trehalose, the SD and XWT temperature trends follow a linear behaviour where the angular coefficient for Glutamine /Water/Trehalose compounds are lower than that of the Glutamine-Water system in both cases. The obtained findings suggest that Trehalose stabilizes Glutamine against heat treatment.

Effects of Monascus application on in vitro digestion and fermentation characteristics of fish protein

The aim of this study was to investigate the digestion and fermentation properties of fish protein fermented by Monascus. Semi-dried fish was fermented by applying Monascus purpureus Went M 3.439. Our results show that the Monascus fermentation of the fish protein enriched the free amino acids and achieved a relatively higher glutamate content than the control group. The Monascus treatment promoted the decomposition of the fish protein during in vitro digestion, reduced the ammonia and indole content and tended to increase the propionic acid content during in vitro fermentation. The Monascus treatment considerably changed the gut microbiota composition, and particularly increased the relative abundance of Parabacteroides in the in vitro fermentation model of human distal colon. Consumption of Monascus fermented fish protein could result in positive changes in fermentation metabolites and gut microbiota, which brings potential health benefits.