Bioactive compounds from regular diet and faecal microbial metabolites

Effects of feeding patterns on production performance, lipo-nutritional quality and gut microbiota of Sunit sheep

This study aimed to investigate the impact of feeding patterns on the production performance, lipo-nutritional quality, and gut microbiota of Sunit sheep. A total of 24 sheep were assigned to two groups: confinement feeding (CF) and pasture feeding (PF) groups. After 90 days, the CF group exhibited significantly increased average daily gain, carcass weight, backfat thickness, and intramuscular fat content of the sheep, whereas the PF group showed significantly increased pH24h and decreased L∗ value and cooking loss of the longissimus lumborum (LL) muscle (P < 0.05). In the PF group, the contents of linoleic, α-linolenic, and docosahexaenoic acids were considerably higher and the n-6/n-3 polyunsaturated fatty acid ratio was significantly lower (P < 0.05). Furthermore, the triglyceride, cholesterol, and nonesterified fatty acid levels in the serum of the CF group significantly increased, whereas the enzyme contents of fatty acid synthase (FASN) and hormone-sensitive lipase (HSL) in the LL muscle of the PF group were markedly elevated (P < 0.05). The PF group also showed altered expression of lipid metabolism-related genes, including upregulated FASN, HSL, fatty acid binding protein 4 (FABP4), and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) (P < 0.05). Meanwhile, differences were observed in the abundance of key bacteria and microbiota functions between the groups. Correlation analysis revealed that production performance and lipid metabolism may be related to the differential effects of bacteria. In conclusion, the transition in the feeding patterns of Sunit sheep caused changes in the gut microbial community and lipid metabolism level in the muscle as well as differences in fat deposition and meat quality.

Changes in gut microbiota linked to a prevention of cardiac remodeling induced by hypertension in spontaneously hypertensive rats fed a pawpaw fruit diet

Objective

Dietary intake of fruit is associated with lower incidence of hypertension and cardiovascular risk. Papaya is a kind of delicious fruit and reported has dietary therapeutic effects, such as digestive stimulation and hypotensive efficacy. However, the mechanism of pawpaw involved have not been elucidated. Here, we illustrate that the effect of pawpaw on the gut microbiota and the prevention of cardiac remodeling.

Methods

Gut microbiome, cardiac structure/function, and blood pressure were examined in SHR and WKY groups. The intestinal barrier was tested with histopathologic; immunostaining and Western blot were used to measure the tight junction protein level; Gpr41 was tested by RT-PCR, and inflammatory factors were detected with ELISA.

Results

We observed a significant decrease in microbial richness, diversity, and evenness is the spontaneously hypertensive rat (SHR), in addition to an increased Firmicutes/Bacteroidetes (F/B) ratio. These changes were accompanied by decreased in acetate and butyrate-producing bacteria. Compared with SHR, treatment with pawpaw at the dosage of 10 g/kg for 12 weeks significantly reduced the blood pressure, cardiac fibrosis and cardiac hypertrophy, while the ratio of F/B decreased. We also found that the concentration of short-chain fatty acids (SCFAs) was increased in SHR fed with pawpaw compared with that in control group, while the gut barrier was restored and level of proinflammatory cytokines in the serum were decreased.

Conclusions

Pawpaw, rich of high fiber, led to changes in the gut microbiota that played a protective role in the development of cardiac remodeling. The potential mechanism of pawpaw may explained by the generation of one of the main metabolites of the gut microbiota, the short-chain fatty acid acetate, increasing tight junction protein level occluding to enhance the gut barrier for less releasing the inflammation cytokines, and upregulating G-protein-coupled receptor 41 (GPR41) to reduce blood pressure.

Feeding Fiber-Bound Polyphenol Ingredients at Different Levels Modulates Colonic Postbiotics to Improve Gut Health in Dogs

Simple Summary

Microbes present in the large intestine of humans and companion animals produce bioactive metabolites from host-ingested food. These bioactive metabolites can influence host health. A prior study in dogs that were healthy or had chronic enteritis/gastroenteritis showed that stool quality improved when they ate food containing a fiber bundle made from fibers of pecan shells, flax seed, cranberry, citrus, and beet. In addition, eating food containing the fiber bundle resulted in the gut bacteria shifting from digesting mainly protein to digesting mainly carbohydrates. The present study tested the impact of the fiber bundle at a lower range of concentrations in dogs. Fecal levels of several bioactive metabolites with beneficial antioxidant or anti-inflammatory properties increased after dogs consumed food with the fiber bundle, though no changes in the bacteria or their functional pathways were observed. Stool quality remained in the acceptable range. These results suggest that the gut bacteria were able to digest the fiber bundle to produce beneficial bioactive metabolites to improve host health.

Abstract

This study assessed changes in canine fecal metabolites and microbiota with the consumption of foods with increasing concentrations of a fiber bundle including pecan shells, flax seed, and powders of cranberry, citrus, and beet that was previously shown (at 14% w/w) to improve stool quality, shift fecal bacterial metabolism from proteolysis to saccharolysis, increase abundance of saccharolytic bacteria, and decrease abundance of proteolytic bacteria. In this study, 48 healthy adult dogs were split evenly to consume different inclusion levels (0%, 1%, 2%, and 4%) of the fiber bundle for a 31-day period following a 28-day pre-feed period. Increases from baseline in the fecal short-chain fatty acids butyric acid, valeric acid, and hexanoic acid were observed only in the dogs that consumed the food with the 4% fiber bundle. With addition of any level of the fiber bundle, increases were seen in the polyphenols hesperidin, hesperetin, ponciretin, secoisolariciresinol diglucoside, secoisolariciresinol, and enterodiol. However, fecal microbiota and their metabolism, and stool scores were largely unaffected by the fiber bundle. Overall, addition of the fiber bundle appeared to increase bioactive metabolites of increased antioxidant and anti-inflammatory potency for beneficial to health and, at levels ≥4%, shifted gut bacterial metabolism toward saccharolysis.

Mineral Composition and Bioaccessibility in Rocket and Purslane after Zn Biofortification Process

Zinc (Zn) is an essential key nutrient in different biochemical and physiological processes. The nutritional deficit of this mineral element is estimated to affect the health of over 3 billion people worldwide. Several strategies are available to reduce the negative impact of mineral malnutrition; among them, biofortification is the practice of deliberately increasing the nutrients and healthy compounds in the edible parts of vegetables. This study aims to evaluate Zn bioaccessibility in biofortified and non-biofortified rocket and purslane using an in vitro gastrointestinal digestion process and measure the concentration of other mineral elements (Al, B, Ca, Fe, K, Mg, Mn, and Sr) released during the digestion process from rocket and purslane biofortified with Zn. The bioaccessible Zn in biofortified rocket and purslane ranged from 7.43 to 16.91 mg/kg, respectively. In addition, the daily intake, the RDA coverage (%), and the hazard quotient (HQ) for the intake of Zn (resulting from the consumption of 100 g of rocket and purslane) were calculated. The calculated HQ highlights the safety of these baby leaf vegetables. The study confirms that it is possible to obtain Zn-biofortified rocket and purslane with high Zn bioaccessibility by adopting an appropriate mineral plant nutrition solution enriched in Zn.

Regulation of Intestinal Barrier Function by Microbial Metabolites

The human gastrointestinal tract (GI) harbors a diverse population of microbial life that continually shapes host pathophysiological responses. Despite readily available abundant metagenomic data, the functional dynamics of gut microbiota remain to be explored in various health and disease conditions. Microbiota generate a variety of metabolites from dietary products that influence host health and pathophysiological functions. Since gut microbial metabolites are produced in close proximity to gut epithelium, presumably they have significant impact on gut barrier function and immune responses. The goal of this review is to discuss recent advances on gut microbial metabolites in the regulation of intestinal barrier function. While the mechanisms of action of these metabolites are only beginning to emerge, they mainly point to a small group of shared pathways that control gut barrier functions. Amidst expanding technology and broadening knowledge, exploitation of beneficial microbiota and their metabolites to restore pathophysiological balance will likely prove to be an extremely useful remedial tool.

Interplay between dietary phenolic compound intake and the human gut microbiome in hypertension: A cross-sectional study

In the present study, potential associations between dietary phenolic compounds (PCs), gut microbiota composition and targeted faecal metabolites were identified in a cross-sectional study including grade 1 hypertensive (HT) and normotensive (NT) subjects. We performed comprehensive quantification of PC intake, together with 16S rRNA gene sequencing of the gut microbiota, and faecal and plasma short-chain fatty acids (SCFAs) determination. The results showed multiple-way relationships between PCs from several plant-based foods and 25 bacterial taxa previously defined as discriminant biomarkers among groups. Remarkably, coffee PCs were positively associated with systolic and diastolic blood pressure, faecal SCFAs, Bacteroides plebeius and Bacteroides coprocola in HT and negatively associated with Faecalibacterium prausnitzii and Christensenellaceae R-7 in NT. Olive fruit PCs were positively associated with Ruminococcaceae UCG-010, Christensenellaceae R-7 and plasma SCFAs in NT. These interplays with discriminant bacterial taxa in HT and NT subjects highlight the potential role of specific PCs as gut microbiome modulators in either the pathogenesis or prevention of hypertension.

New players in the relationship between diet and microbiota: the role of macromolecular antioxidant polyphenols

PURPOSE

Solid evidence has emerged supporting the role of polyphenols and fibers as gut microbiota modulators. These studies have been limited to the data available in food composition databases, which did not include the food content of non-extractable polyphenols (NEPP). The main objective of this work is to quantify the intake of the different types of dietary polyphenols including NEPP and to evaluate their impact on the composition and activity of the intestinal microbiota.

METHODS

Cross-sectional descriptive study conducted on a sample of 147 adults with no declared pathologies. Dietary intake has been registered by a semi-quantitative Food Frequency Questionnaire (FFQ) and transformed into extractable (EPP) and NEPP, and dietary fibers based on available databases. Major phylogenetic types of the intestinal microbiota were determined by qPCR and fecal SCFA quantification was performed by gas chromatography.

RESULTS

NEPP account for two-thirds of the total polyphenols intake. A combined analysis by stepwise regression model including all dietary fiber and (poly)phenols has identified hydrolysable (poly)phenol (HPP) intake, as the best predictor of Bacteroides-Prevotella-Porphyromonas group and Bifidobacterium levels in feces. Also, HPPs were positively associated with butyric acid, while insoluble fiber was identified as a predictor of propionic acid in feces.

CONCLUSION

The intake of macromolecular (poly)phenols could contribute to modulate the gut microbiota by increasing the levels of certain intestinal microorganisms with proven health benefits.

An Overview on Fecal Branched Short-Chain Fatty Acids Along Human Life and as Related With Body Mass Index: Associated Dietary and Anthropometric Factors

Short-chain fatty acids (SCFA) are the main bacterial products of the catabolism of carbohydrates and proteins in the gut, and their role is essential in host–microbiota interactions. Acetic, propionic, and butyric acids are the major SCFA produced in the gut, and they have been extensively studied. In contrast, branched short-chain fatty acids (BCFA), mainly isovaleric and isobutyric acids, are produced in less amounts and their fecal levels in different human groups, intestinal microbial producing populations, and influence on health are insufficiently known. They have been proposed as markers of protein fermentation, which leads to the concomitant production of other fermentation products that can be harmful for the colon epithelium. In this context, the aim of this study was to shed light into the production of BCFA by the human intestinal microbiota, as related to age, body mass index (BMI), and diet. Fecal levels of the different SCFA were analyzed by gas chromatography in 232 healthy individuals with ages between 3 months and 95 years, and BMI in adults ranging from 19 to 54. Dietary assessments in adults were obtained through a food frequency questionnaire (FFQ). Molar proportions of BCFA in feces were strongly and positively related with aging. However, not a significant relationship was obtained between BCFA and BMI. A negative correlation was found between the consumption of dietary insoluble fiber and fecal levels of BCFA. More studies are needed for improving our understanding on the relationship of BCFA production profile with the intestinal microbiota composition and human health.

Diet, nutrients and the microbiome

Although there is associative evidence linking fecal microbiome profile to health and disease, many studies have not considered the confounding effects of dietary intake. Consuming food provides fermentable substrate which sustains the microbial ecosystem that resides with most abundance in the colon. Western, Mediterranean and vegetarian dietary patterns have a role in modulating the gut microbiota, as do trending restrictive diets such the paleolithic and ketogenic. Altering the amount or ratio of carbohydrate, protein and fat, particularly at the extremes of intake, impacts the microbiome. Diets high in fermentable carbohydrates support the relative abundance of Bifidobacterium, Prevotella, Ruminococcus, Dorea and Roseburia, among others, capable of degrading polysaccharides, oligosaccharides and sugars. Conversely, very high fat diets increase bile-resistant organisms such as Bilophila and Bacteroides. Food form, whole foods vs. ultra-processed, alters the provision of macronutrient substrate to the colon due to differing digestibility, and thereby may impact the microbiota and its metabolic activity. In addition, phytochemicals in plant-based foods have specific and possibly prebiotic effects on the microbiome. Further, food ingredients such as certain low-calorie sweeteners enhance Bifidobacterium spp. The weight of evidence to date suggests a high level of interindividual variability in the human microbiome vs. clearly defined, dietary-induced profiles. Healthful dietary patterns, emphasizing plant foods high in microbial-available carbohydrate, support favorable microbiome profiles active in saccharolytic fermentation. Future research into diet and microbiome should consider the balance of gut microbial-generated metabolites, an important link between microbiome profile and human health.

Fermented Dairy Foods: Impact on Intestinal Microbiota and Health-Linked Biomarkers

The intake of fermented foods is gaining increasing interest due to their health-promoting benefits. Among them, fermented dairy foods have been associated with obesity prevention, and reduction of the risk of metabolic disorders and immune-related pathologies. Fermented foods could lead to these health benefits by providing the consumer with both easily metabolizable nutrients and beneficial microorganisms. Our aim was to evaluate the relationship between the consumption of fermented dairy products and the intestinal microbiota, serum lipid profile, and the pro-oxidant/inflammatory status. 130 healthy adults were evaluated. Dietary fermented food intake was assessed by an annual food frequency questionnaire (FFQ), including 26 fermented dairy products. Levels of the major phylogenetic types of the intestinal microbiota were determined by qPCR, and concentration of fecal short chain fatty acids were assessed by gas chromatography. Serum glucose and lipid profile, as well as serum malondialdehyde (MDA), C-reactive protein (CRP), and leptin levels were determined by standardized protocols. Among fermented dairy foods, natural yogurt, sweetened yogurt and matured/semi-matured cheese were the most consumed. While natural yogurt consumers showed increased fecal levels of Akkermansia with respect to non-consumers, sweetened yogurt intake was associated to lower levels of Bacteroides. Serum levels of CRP were also significantly reduced in yogurt consumers. Our results underline the interest in exploring the potential effects of the different yogurt types and the role the microbiota may play in such effects.

Balance of saccharolysis and proteolysis underpins improvements in stool quality induced by adding a fiber bundle containing bound polyphenols to either hydrolyzed meat or grain-rich foods

Dietary fiber is a key component in gastrointestinal health maintenance partly due to its fermentation by the gut microbiome. The food-dependent effects of a novel fiber bundle added to hydrolyzed meat (HM) or grain-rich (GR) foods in healthy dogs (n = 16) or those with chronic enteritis/gastroenteritis (n = 16) were examined. Addition of fiber to either food improved stool quality in dogs regardless of health status; microbiome diversity of dogs with chronic enteritis/gastroenteritis became more similar to healthy dogs. The abundance of bacteria mediating beneficial saccharolytic processes (eg, Lachnospiraceae) significantly increased on addition of fiber to the GR food, while those mediating detrimental proteolytic catabolism (eg, Desulfovibrionaceae) significantly decreased. Fiber addition to the HM food led to significant changes in saccharolytic/proteolytic bacteria. Higher levels of free saccharides in feces upon fiber addition to either food indicated increased saccharolysis. Fiber addition to the GR food decreased levels of fecal free amino acids, indicating decreased proteolysis. Addition of fiber decreased fecal pH for both foods but likely by different mechanisms: addition of fiber to the HM food led to increased straight-chain short-chain fatty acids (SCFAs) and no significant change in proteolytic branched-chain SFCAs, while in the GR food, fiber mainly led to decreased proteolytic branched-chain SFCAs. Other postbiotics related to intestinal health were consistently altered when fiber was added to either food. Plant-derived bioactive molecules were enriched in feces from dogs fed either food with added fiber, which could account for the observed modulation of the canine gut microbiome and shifts in metabolic capacity.

Effects of dietary energy levels on rumen bacterial community composition in Holstein heifers under the same forage to concentrate ratio condition

Background

The rumen bacterial community plays a critical role in feeds degradation and productivity. The effects of different forage to concentrate ratios on the ruminal microbial population structure have been studied extensively; however, research into changes in the ruminal bacterial community composition in heifers fed different energy level diets, with the same forage to concentrate ratio, has been very limited. The purpose of this study was to investigate the effects of different dietary energy levels, with the same forage to concentrate ratio, on ruminal bacterial community composition of heifers. Furthermore, we also determine the relationship between rumen bacteria and ruminal fermentation parameters.

Results

The 16S rRNA gene sequencing showed that, under the same forage to concentrate ratio of 50:50, an 8% difference in dietary energy level had no significant impact on the alpha diversity and the relative abundance of the major phyla and most of the major genera in heifers. In all the treatments groups, Firmicutes, Bacteroidetes, and Proteobacteria were the dominant phyla. Spearman correlation analysis between the relative abundances of the rumen bacteria at the genus level and the fermentation parameters showed that the relative abundances of Prevotella and BF311 were positively correlated with the ammonia nitrogen and butyrate concentrations, and these two genera were negatively correlated with the propionate and isovalerate concentrations, respectively, and the genus Bifidobacterium was positively correlated with the butyrate concentration and was negatively correlated with propionate and isovalerate concentration. The total volatile fatty acid concentration was positively correlated with BF311 abundances, and was negatively correlated with Trichococcus and Facklamia abundances.

Conclusions

Under the same forage to concentrate ratio condition of 50:50, an 8% difference in dietary energy levels had little impact on rumen bacterial community composition in heifers. The correlations between some genera of ruminal bacteria and the concentrations of volatile fatty acids and ammonia nitrogen might be indicative that the ruminal fermentation parameters are strongly influenced by the rumen bacterial community composition.