Pea polyphenolics and hydrolysis processing alter microbial community structure and early pathogen colonization in mice

Modulation of gut-microbiota through probiotics and dietary interventions to improve host health

Dietary patterns play an important role in regards to the modulation and control of the gut microbiome composition and function. The interaction between diet and microbiota plays an important role in order to maintain intestinal homeostasis, which ultimately affect the host's health. Diet directly impacts the microbes that inhabit the gastrointestinal tract (GIT), which then contributes to the production of secondary metabolites, such as short-chain fatty acids, neurotransmitters, and antimicrobial peptides. Dietary consumption with genetically modified probiotics can be the best vaccine delivery vector and protect cells from various illnesses. A holistic approach to disease prevention, treatment, and management takes these intrinsically linked diet-microbes, microbe-microbe interactions, and microbe-host interactions into account. Dietary components, such as fiber can modulate beneficial gut microbiota, and they have resulting ameliorative effects against metabolic disorders. Medical interventions, such as antibiotic drugs can conversely have detrimental effects on gut microbiota by disputing the balance between Bacteroides and firmicute, which contribute to continuing disease states. We summarize the known effects of various dietary components, such as fibers, carbohydrates, fatty acids, vitamins, minerals, proteins, phenolic acids, and antibiotics on the composition of the gut microbiota in this article in addition to the beneficial effect of genetically modified probiotics and consequentially their role in regards to shaping human health. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Gut microbiota-mediated polyphenol metabolism is restrained by parasitic whipworm infection and associated with altered immune function in mice

Polyphenols are phytochemicals commonly found in plant-based diets which have demonstrated immunomodulatory and anti-inflammatory properties. However, the interplay between polyphenols and pathogens at mucosal barrier surfaces has not yet been elucidated in detail. Here, we show that proanthocyanidin (PAC) polyphenols interact with gut parasites to influence immune function and gut microbial-derived metabolites in mice. PAC intake inhibited mastocytosis during infection with the small intestinal roundworm Heligmosomoides polygyrus, and altered the host tissue transcriptome at the site of infection with the large intestinal whipworm Trichuris muris, with a notable enhancement of type-1 inflammatory and interferon-driven gene pathways. In the absence of infection, PAC intake promoted the expansion of Turicibacter within the gut microbiota, increased fecal short chain fatty acids, and enriched phenolic metabolites such as phenyl-γ-valerolactones in the cecum. However, these putatively beneficial effects were reduced in PAC-fed mice infected with T. muris, suggesting concomitant parasite infection can attenuate gut microbial-mediated PAC catabolism. Collectively, our results suggest an inter-relationship between a phytonutrient and infection, whereby PAC may augment parasite-induced inflammation (most prominently with the cecum dwelling T. muris), and infection may abrogate the beneficial effects of health-promoting phytochemicals.

Consumption of the cell-free or heat-treated fractions of a pitched kefir confers some but not all positive impacts of the corresponding whole kefir

Introduction

Kefir consumption can have many metabolic health benefits, including, in the case of specific kefirs, improvements in plasma and liver lipid profiles. Our group has previously shown that these health benefits are dependent on the microbial composition of the kefir fermentation, and that a pitched kefir (PK1) containing specific traditional microbes can recapitulate the health benefits of a traditional kefir. In this study we investigated how different preparations of kefir impact cholesterol and lipid metabolism and circulating markers of cardiovascular disease risk and determine if freeze-drying impacts health benefits relative to past studies.

Materials and methods

Eight-week-old male and female C57Bl/6 mice were fed a high fat diet (40% kcal from fat) supplemented with one of 3 freeze-dried kefir preparations (whole kefir, cell-free kefir, or heat-treated kefir) for 8 weeks prior to analysis of plasma and liver lipid profiles, circulating cardiovascular disease (CVD) biomarkers, cecal microbiome composition, and cecal short-chain fatty acid levels. These groups of mice were compared to others that were fed a control low-fat diet, control high fat diet or high fat diet supplemented with milk, respectively.

Results

All kefir preparations lowered plasma cholesterol in both male and female mice, while only whole kefir lowered liver cholesterol and triglycerides. Plasma vascular cell adhesion molecule 1 (VCAM-1) was lowered by both whole kefir and heat-treated kefir in male mice but not females, while c-reactive protein (CRP) was unchanged across all high fat diet fed groups in males and females.

Conclusion

These results indicate that some of the metabolic benefits of consumption of this kefir do not require whole kefir while also indicating that there are multiple compounds or components responsible for the different benefits observed.

The Use of Disinfectant in Barn Cleaning Alters Microbial Composition and Increases Carriage of Campylobacter jejuni in Broiler Chickens

To maintain food safety and flock health in broiler chicken production, biosecurity approaches to keep chicken barns free of pathogens are important. Canadian broiler chicken producers must deep clean their barns with chemical disinfectants at least once annually (full disinfection [FD]) and may wash with water (water wash [WW]) throughout the year. However, many producers use FD after each flock, assuming a greater efficacy of more stringent cleaning protocols, although little information is known regarding how these two cleaning practices affect pathogen population and gut microbiota. In the present study, a crossover experiment over four production cycles was conducted in seven commercial chicken barns to compare WW and FD. We evaluated the effects of barn cleaning methods on commercial broiler performance, cecal microbiota composition, Campylobacter and Salmonella occurrence, and Campylobacter jejuni and Clostridium perfringens abundance, as well as on short-chain fatty acid (SCFA) concentrations in the month-old broiler gut. The 30-day body weight and mortality rate were not affected by the barn cleaning methods. The WW resulted in a modest but significant effect on the structure of broiler cecal microbiota (weighted-UniFrac; adonis P = 0.05, and unweighted-UniFrac; adonis P = 0.01), with notable reductions in C. jejuni occurrence and abundance. In addition, the WW group had increased cecal acetate, butyrate, and total SCFA concentrations, which were negatively correlated with C. jejuni abundance. Our results suggest that WW may result in enhanced activity of the gut microbiota and reduced zoonotic transmission of C. jejuni in broiler production relative to FD in the absence of a disease challenge. IMPORTANCE We compared the effects of barn FD and WW methods on gut microbial community structures and pathogen prevalence of broiler chickens in a nonchallenging commercial production setting. The results revealed that barn cleaning methods had little impact on the 30-day body weight and mortality rate of broiler chickens. In addition, the FD treatment had a subtle but significant effect on the broiler cecal microbiota with increased abundances of Campylobacter and decreased SCFA concentrations, which would support the adoption of WW as a standard practice. Thus, compared to FD, WW can be beneficial to broiler chicken production by inhibiting zoonotic pathogen colonization in the chicken gut with reduced cost and labor of cleaning.

Hyaluronan-induced alterations of the gut microbiome protects mice against Citrobacter rodentium infection and intestinal inflammation

Hyaluronan is a glycosaminoglycan polymer that has been shown to play an important role in homeostasis of the gastrointestinal tract. However, its mechanistic significance in gastrointestinal epithelial barrier elements remain unexplored. Here, our results revealed that hyaluronan treatment resulted in significant changes in the gut microbiota in mice. To demonstrate the functional consequences of hyaluronan-treatment and hyaluronan-induced microbiota alterations, Citrobacter rodentium- and DSS-induced colitis models and microbiota transplantation approaches were utilized. We showed that hyaluronan alleviated intestinal inflammation in both pathogen and chemically induced intestinal mucosal damage. The protection in bacterial colitis was associated with enhanced C. rodentium clearance and alleviation of pathogen-induced gut dysbiosis. Microbiota transplantation experiments showed that the hyaluronan-altered microbiota is sufficient to confer protection against C. rodentium infection. Colonization with Akkermansia muciniphila, a commensal bacterium that is greatly enriched by hyaluronan treatment, alleviated C. rodentium-induced bacterial colitis in mice. Additionally, Akkermansia-induced protection was found to be associated with the induction of goblet cells and the production of mucins and epithelial antimicrobial peptides. Collectively, these results provide novel insights into the regulatory role of hyaluronan in modulating the gut microbiota and immunity in enteric infection and inflammation, with therapeutic potential for gut microbiome-targeted immunotherapy.

Jaboticaba (Myrciaria jaboticaba) powder consumption improves the metabolic profile and regulates gut microbiome composition in high-fat diet-fed mice

The consumption of a high-fat diet can cause metabolic syndrome and induces host gut microbial dysbiosis and non-alcoholic fatty liver disease (NAFLD). We evaluated the effect of polyphenol-rich jaboticaba peel and seed powder (JPSP) on the gut microbial community composition and liver health in a mouse model of NAFLD. Three-month-old C57BL/6 J male mice, received either a control (C, 10% of lipids as energy, n = 16) or high-fat (HF, 50% of lipids as energy, n = 64) diet for nine weeks. The HF mice were randomly subdivided into four groups (n = 16 in each group), three of which (HF-J5, HF-J10, and HF-J15) were supplemented with dietary JPSP for four weeks (5%, 10%, and 15%, respectively). In addition to attenuating weight gain, JPSP consumption improved dyslipidemia and insulin resistance. In a dose-dependent manner, JPSP consumption ameliorated the expression of hepatic lipogenesis genes (AMPK, SREBP-1, HGMCoA, and ABCG8). The effects on the microbial community structure were determined in all JPSP-supplemented groups; however, the HF-J10 and HF-J15 diets led to a drastic depletion in the species of numerous bacterial families (Bifidobacteriaceae, Mogibacteriaceae, Christensenellaceae, Clostridiaceae, Dehalobacteriaceae, Peptococcaceae, Peptostreptococcaceae, and Ruminococcaceae) compared to the HF diet, some of which represented a reversal of increases associated with HF. The Lachnospiraceae and Enterobacteriaceae families and the Parabacteroides, Sutterella, Allobaculum, and Akkermansia genera were enriched more in the HF-J10 and HF-J15 groups than in the HF group. In conclusion, JPSP consumption improved obesity-related metabolic profiles and had a strong impact on the microbial community structure, thereby reversing NAFLD and decreasing its severity.

Regulation of Enteric Infection and Immunity by Dietary Proanthocyanidins

The role of dietary components in immune function has acquired considerable attention in recent years. An important focus area is to unravel the role of bioactive dietary compounds in relation to enteric disease and their impact on gut mucosal immunity. Proanthocyanidins (PAC) are among the most common and most consumed dietary polyphenols, and are characterised by their variable molecular structures and diverse bioactivities. In particular, their anti-oxidative effects and ability to modulate gut microbiota have been widely described. However, there is limited evidence on the mechanism of action of PAC on the immune system, nor is it clearly established how PAC may influence susceptibility to enteric infections. Establishing the sites of action of PAC and their metabolites within the gut environment is fundamental to determine the applicability of PAC against enteric pathogens. Some mechanistic studies have shown that PAC have direct modulatory effects on immune cell signalling, isolated pathogens, and gut mucosal barrier integrity. Boosting the recruitment of immune cells and suppressing the amount of pro-inflammatory cytokines are modulating factors regulated by PAC, and can either be beneficial or detrimental in the course of re-establishing gut homeostasis. Herein, we review how PAC may alter distinct immune responses towards enteric bacterial, viral and parasitic infections, and how the modulation of gut microbiota may act as a mediating factor. Furthermore, we discuss how future studies could help unravel the role of PAC in preventing and/or alleviating intestinal inflammation and dysbiosis caused by enteric disease.

Early-life supplementation of grape polyphenol extract promotes polyphenol absorption and modulates the intestinal microbiota in association with the increase in mRNA expression of the key intestinal barrier genes

Early-life nutritional supplementation can dramatically influence health status. Dietary polyphenols are a widespread group of phytochemicals with potential bioactive functions. However, how polyphenol intake during early life affects health status remains largely unknown. Mice aged 3- and 6-weeks were used to investigate how grape polyphenol extract (GPE) administration during early life altered polyphenol absorption, the intestinal microbiota, and the intestinal barrier. After a 2-week GPE supplementation, there were more diverse polyphenol metabolites in the plasma of 3-week-old mice than in the plasma of 6-week-old mice. Correspondingly, GPE supplementation increased the mRNA expression of genes related to polyphenol absorption in 3-week-old mice but not 6-week-old mice. Early-life GPE administration also stimulated the key genes of the small intestinal barrier in mice. Moreover, the key genes of the small intestinal barrier were positively associated with the genes related to polyphenol absorption in the small intestine of 3-week-old mice. In addition, fecal Akkermansia and Lactobacillus were increased, as evidenced by 16S rRNA gene sequencing. As a result, the acetate and butyrate production in the large intestinal content was enhanced, and the mRNA expression of the key genes involved in the large intestinal barrier was also increased. Thus, our study demonstrates that dietary polyphenol intake in early life induces improvements in polyphenol absorption, the intestinal microbiota, and the intestinal barrier, suggesting the importance of polyphenol-rich nutritional programming during early life on health status.

Impact of dietary components on enteric infectious disease

Diets impact host health in multiple ways and an unbalanced diet could contribute to the initiation or progression of a variety of diseases. Although a wealth of information exists on the connections between diet and chronic metabolic diseases such as cardiovascular disease, diabetes mellitus, etc., how diet influences enteric infectious disease still remain underexplored. The review summarizes the current findings on the link between various dietary components and diverse enteric infectious diseases. Dietary ingredients discussed include macronutrients (carbohydrates, lipids, proteins), micronutrients (vitamins, minerals), and other dietary ingredients (phytonutrients and probiotic supplements). We first describe the importance of enteric infectious diseases and the direct and indirect relationship between diet and enteric infectious diseases. Then we discuss the effects of different dietary components on the susceptibility to or progression of enteric infectious disease. Finally, we delineate current knowledge gap and highlighted future research directions. The literature review revealed that different dietary components affect host resistance to enteric infections through a variety of mechanisms. Dietary components may directly inhibit or bind to enteric pathogens, or indirectly influence enteric infections through modulating immune function and gut microbiota. Elucidating the unique repercussions of different diets on enteric infections in this review may help provide dietary guidelines or design dietary interventions to prevent or alleviate enteric infectious diseases.

The impact of maternal and early life malnutrition on health: a diet-microbe perspective

BACKGROUND

Early-life malnutrition may have long-lasting effects on microbe-host interactions that affect health and disease susceptibility later in life. Diet quality and quantity in conjunction with toxin and pathogen exposure are key contributors to microbe-host physiology and malnutrition. Consequently, it is important to consider both diet- and microbe-induced pathologies as well as their interactions underlying malnutrition.

MAIN BODY

Gastrointestinal immunity and digestive function are vital to maintain a symbiotic relationship between the host and microbiota. Childhood malnutrition can be impacted by numerous factors including gestational malnutrition, early life antibiotic use, psychological stress, food allergy, hygiene, and exposure to other chemicals and pollutants. These factors can contribute to reoccurring environmental enteropathy, a condition characterized by the expansion of commensal pathobionts and environmental pathogens. Reoccurring intestinal dysfunction, particularly during the critical window of development, may be a consequence of diet-microbe interactions and may lead to life-long immune and metabolic programming and increased disease risk. We provide an overview of the some key factors implicated in the progression of malnutrition (protein, fat, carbohydrate, iron, vitamin D, and vitamin B12) and discuss the microbiota during early life that may contribute health risk later in life.

CONCLUSION

Identifying key microbe-host interactions, particularly those associated with diet and malnutrition requires well-controlled dietary studies. Furthering our understanding of diet-microbe-host interactions will help to provide better strategies during gestation and early life to promote health later in life.

Diet-Microbe-Host Interactions That Affect Gut Mucosal Integrity and Infection Resistance

The gastrointestinal tract microbiome plays a critical role in regulating host innate and adaptive immune responses against pathogenic bacteria. Disease associated dysbiosis and environmental induced insults, such as antibiotic treatments can lead to increased susceptibility to infection, particularly in a hospital setting. Dietary intervention is the greatest tool available to modify the microbiome and support pathogen resistance. Some dietary components can maintain a healthy disease resistant microbiome, whereas others can contribute to an imbalanced microbial population, impairing intestinal barrier function and immunity. Characterizing the effects of dietary components through the host-microbe axis as it relates to gastrointestinal health is vital to provide evidence-based dietary interventions to mitigate infections. This review will cover the effect of dietary components (carbohydrates, fiber, proteins, fats, polyphenolic compounds, vitamins, and minerals) on intestinal integrity and highlight their ability to modulate host-microbe interactions as to improve pathogen resistance.