Prebiotic potential of mushroom d-glucans: implications of physicochemical properties and structural features

Mushroom d-glucans are recognized as dietary fibers and as biologically active natural polysaccharides, with the advantages of being quite inexpensive for production, tolerable, and having a range of possible structures and physicochemical properties. The prebiotic potential of mushroom d-glucans has been explored in recent years, but the relationship between their various structural features and activity is poorly understood. This review focuses on comprehensively evaluating the prebiotic potential of mushroom d-glucans in face of their structural variations. Overall, mushroom d-glucans provide a unique set of different structures and physicochemical properties with prebiotic potential, where linkage type and solubility degree seem to be associated with prebiotic activity outcomes. The understanding of the effects of distinct structures and physicochemical properties in mushroom d-glucans on the gut microbiota contributes to the design and selection of new prebiotics in a more predictable way.

Polysaccharide of Atractylodes macrocephala Koidz regulates LPS-mediated mouse hepatitis through the TLR4-MyD88-NFκB signaling pathway

Feed corruption and poor breeding environment could cause widespread bacterial infection which could cause severe liver inflammation and lead to liver damage, even death. It has been proved that Polysaccharide of Atractylodes macrocephala Koidz (PAMK) could improve the immunity of animal, but the mechanism of its protective effect on hepatitis has been rarely reported. This study investigated the protective effect of PAMK on mouse liver through LPS-induced liver inflammatory. The results showed that LPS caused swelling of hepatocytes, disappearance of hepatic cord structure and infiltration of a large number of inflammatory cells, and LPS could up-regulated mRNA and protein expression levels of TLR4, MyD88, IKBα and NFκB, increased cytokines IL-1β, IL-4, IL-6 and TNF-α levels, enhance the levels of antioxidant enzymes CAT, GSH-PX, SOD, iNOs and MDA. PAMK pretreatment could relieved histopathological damage caused by LPS, and could activate the TLR4-MyD88-NFκB signalling pathway, reduce the levels of IL-1β, IL-6 and TNF-α, increase IL-4 levels, inhibit the levels of GSH-PX and MDA. These results indicate that PAMK could reduce inflammatory damage and oxidative stress in mice and play a protective role in the early stages of LPS invasion of the liver.

Maternal stevioside supplementation ameliorates intestinal mucosal damage and modulates gut microbiota in chicken offspring challenged with lipopolysaccharide

Our previous study showed that dietary stevioside supplementation could alleviate intestinal mucosal damage induced by lipopolysaccharide (LPS) through its anti-inflammatory and antioxidant effects in broiler chickens. However, it remains unknown whether feeding stevioside to breeder hens could exert similar biological functions in their offspring. The present study aimed to investigate whether maternal dietary stevioside supplementation could prevent LPS-induced intestinal mucosal damage and alteration of gut microbiota in chicken offspring. A total of 120 Jinmao yellow-feathered breeder hens were fed a basal diet (CON) or a 250 mg kg^-1 stevioside-supplemented diet (STE) for 5 weeks before collecting their eggs. After hatching, 160 male offspring (80 chickens from each group) were randomly selected and divided into four treatment groups: (1) the offspring of hens fed a basal diet (CON); (2) the offspring of hens fed a stevioside-supplemented diet (STE); (3) the CON group challenged with LPS (LPS); and (4) the STE group challenged with LPS (LSTE). The results showed that maternal stevioside supplementation increased the hatching weight and improved the intestinal morphology. LPS challenge significantly decreased the terminal body weight and the concentrations of serum triglyceride (TG) and glucose (GLU) of the chicken offspring. Maternal stevioside supplementation protected against LPS-induced morphological damage, goblet cell impairment, intestinal apoptosis, and gene expression alteration. In addition, sequence analysis of 16S rRNA gene showed that maternal stevioside supplementation could prevent the impairment of bacterial diversity in LPS-challenged chicken offspring. Moreover, the increased abundance of Lactobacillus caused by maternal stevioside supplementation had a significant negative correlation with the expression of intestinal inflammatory cytokines. In conclusion, maternal stevioside supplementation could ameliorate intestinal mucosal damage and modulate gut microbiota in chicken offspring challenged with LPS.

Dietary Fiber Ameliorates Lipopolysaccharide-Induced Intestinal Barrier Function Damage in Piglets by Modulation of Intestinal Microbiome

Weaning of piglets is accompanied by intestinal inflammation, impaired intestinal barrier function, and intestinal microflora disorder. Regulating intestinal microflora structure can directly or indirectly affect intestinal health and host growth and development. However, whether dietary fiber (DF) affects the inflammatory response and barrier function by affecting the intestinal microflora and its metabolites is unclear. In this study, we investigated the role of intestinal microflora in relieving immune stress and maintaining homeostasis using piglets with lipopolysaccharide (LPS)-induced intestinal injury as a model. DF improved intestinal morphology and barrier function, inhibited the expression of inflammatory signal pathways (Toll-like receptor 2 [TLR2], TLR4, and NF-κB) and proinflammatory cytokines (interleukin 1β [IL-1β], IL-6, and tumor necrosis factor alpha [TNF-α]), and upregulated the expression of barrier-related genes (encoding claudin-1, occludin, and ZO-1). The contents of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and the activity of diamine oxidase in plasma were decreased. Meanwhile, DF had a strong effect on the composition and function of intestinal microflora at different taxonomic levels, the relative abundances of cellulolytic bacteria and anti-inflammatory bacteria were increased, and the concentrations of propionate, butyrate, and total short-chain fatty acids (SCFAs) in intestinal contents were increased. In addition, the correlation analysis also revealed the potential relationship between metabolites and certain intestinal microflora, as well as the relationship between metabolites and intestinal morphology, intestinal gene expression, and plasma cytokine levels. These results indicate that DF improves intestinal barrier function, in part, by altering intestinal microbiota composition and increasing the synthesis of SCFAs, which subsequently alleviate local and systemic inflammation.IMPORTANCE Adding DF to the diet of LPS-challenged piglets alleviated intestinal and systemic inflammation, improved intestinal barrier function, and ultimately alleviated the growth retardation of piglets. In addition, the addition of DF significantly increased the relative abundance of SCFA-producing bacteria and the production of SCFAs. We believe that the improvement of growth performance of piglets with LPS-induced injury can be attributed to the beneficial effects of DF on intestinal microflora and SCFAs, which reduced the inflammatory response in piglets, improving intestinal barrier function and enhancing body health. These research results provide a theoretical basis and guidance for the use of specific fiber sources in the diet to improve intestinal health and growth performance of piglets and thus alleviate weaning stress. Our data also provide insights for studying the role of DF in regulating gastrointestinal function in human infants.

Health benefits of edible mushroom polysaccharides and associated gut microbiota regulation

Edible mushrooms have been an important part of the human diet for thousands of years, and over 100 varieties have been cultivated for their potential human health benefits. In recent years, edible mushroom polysaccharides (EMPs) have been studied for their activities against obesity, inflammatory bowel disease (IBD), and cancer. Particularly, accumulating evidence on the exact causality between these health risks and specific gut microbiota species has been revealed and characterized, and most of the beneficial health effects of EMPs have been associated with its reversal impacts on gut microbiota dysbiosis. This demonstrates the key role of EMPs in decreasing health risks through gut microbiota modulation effects. This review article compiles and summarizes the latest studies that focus on the health benefits and underlying functional mechanisms of gut microbiota regulation via EMPs. We conclude that EMPs can be considered a dietary source for the improvement and prevention of several health risks, and this review provides the theoretical basis and technical guidance for the development of novel functional foods with the utilization of edible mushrooms.

Postnatal growth retardation is associated with deteriorated intestinal mucosal barrier function using a porcine model

Individuals with postnatal growth retardation (PGR) are prone to developing chronic diseases. Abnormal development in small intestine is casually implicated in impaired growth. However, the exact mechanism is still implausible. In this present study, PGR piglets (aged 42 days) were employed as a good model to analyze developmental changes in intestinal mucosal barrier function. Our data demonstrated that PGR piglets exhibited impaired jejunal and ileal epithelial villous morphology and permeability, accompanied by decreased cell proliferation ability and increased apoptosis rate. In addition, the expression of tight junction proteins (ZO-1, claudin 1, and occludin) and E-cadherin was markedly inhibited by PGR. The expression of P-glycoprotein was significantly reduced in PGR piglets, as well as decreased activity of lysozyme. Moreover, the mRNA abundance and content of inflammatory cytokines were significantly increased in the intestinal mucosa and plasma of PGR piglets, respectively. PGR also contributed to lower level of sIgA, and higher level of CD68-positive rate, β-defensins, and protein expression involved p38 MAPK/NF-κB pathway. Furthermore, PGR altered the intestinal microbial community such as decreased genus Alloprevotella and Oscillospira abundances, and led to lower microbial-derived butyrate production, which may be potential targets for treatment. Collectively, our findings indicated that the intestinal mucosal barrier function of PGR piglets could develop the nutritional intervention strategies in prevention and treatment of the intestinal mucosal barrier dysfunction in piglets and humans.

Xylooligosaccharide attenuates lipopolysaccharide-induced intestinal injury in piglets via suppressing inflammation and modulating cecal microbial communities

Xylooligosaccharide (XOS) has been considered to be an effective prebiotic, but its exact mechanisms remain unknown. This research was conducted to evaluate the effects of XOS on pig intestinal bacterial community and mucosal barrier using a lipopolysaccharide (LPS)-caused gut damage model. Twenty-four weaned pigs were assigned to 4 treatments in a 2 × 2 factorial design involving diet (with or without XOS) and immunological challenge (saline or LPS). After 21 d of feeding 0% or 0.02% commercial XOS product, piglets were treated with saline or LPS. After that, blood, small intestinal mucosa and cecal digesta were obtained. Dietary XOS enhanced intestinal mucosal integrity demonstrated by higher villus height, villus height-to-crypt depth ratio, disaccharidase activities and claudin-1 protein expression and lower crypt depth. XOS also caused down-regulation of the gene expression of toll-like receptor 4 and nucleotide-binding oligomerization domain protein signaling, accompanied with decreased pro-inflammatory cytokines and cyclooxygenase 2 contents or mRNA expression and increased heat shock protein 70 mRNA and protein expression. Additionally, increased Bacteroidetes and decreased Firmicutes relative abundance were observed in the piglets fed with XOS. At the genus level, XOS enriched the relative abundance of beneficial bacteria, e.g., Faecalibacterium, Lactobacillus, and Prevotella. Moreover, XOS enhanced short chain fatty acids contents and inhibited histone deacetylases. The correlation analysis of the combined datasets implied some potential connections between the intestinal microbiota and pro-inflammatory cytokines or cecal metabolites. These results suggest that XOS inhibits inflammatory response and beneficially modifies microbes and metabolites of the hindgut to protect the intestine from inflammation-related injury.

Necroptosis is active and contributes to intestinal injury in a piglet model with lipopolysaccharide challenge

Necroptosis, a newly discovered form of programmed cell death that combines the features of apoptosis and necrosis, is important in various physiological and pathological disorders. However, the role of necroptosis on intestinal injury during sepsis has been rarely evaluated. This study aimed to investigate the presence of necroptosis in intestinal injury, and its contribution to intestinal injury in a piglet model challenged with Escherichia coli lipopolysaccharide (LPS). Firstly, a typical cell necrotic phenomenon was observed in jejunum of LPS-challenged pigs by transmission electron microscope. Protein expression of necroptosis signals including receptor-interacting protein kinase (RIP) 1, RIP3, and phosphorylated mixed-lineage kinase domain-like protein (MLKL), mitochondrial proteins including phosphoglycerate mutase family member 5 (PGAM5) and dynamin-related protein 1 (DRP1), and cytoplasmic high-mobility group box 1 (HMGB1) were time-independently increased in jejunum of LPS-challenged piglets, which was accompanied by the impairment of jejunal morphology, and digestive and barrier function indicated by lower activities of jejunal disaccharidases and protein expression of jejunal tight junction proteins claudin-1 and occludin. Pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 were also dynamically induced in serum and jejunum of piglets after LPS challenge. Moreover, pretreatment with necrostatin-1 (Nec-1), an specific inhibitor of necroptosis, inhibited necroptosis indicated by decreased necrotic ultrastructural changes and decreased protein expression of RIP1, RIP3, and phosphorylated MLKL as well as PGAM5, DRP1, and cytoplasmic HMGB1. Nec-1 pretreatment reduced jejunal morphological injury, and improved digestive and barrier function. Nec-1 pretreatment also decreased the levels of serum and jejunal pro-inflammatory cytokines and the numbers of jejunal macrophages and monocytes. These findings indicate for the first time that necroptosis is present and contributes to LPS-induced intestinal injury. Nec-1 may have a preventive effect on intestinal injury during sepsis.

Dietary genistein supplementation protects against lipopolysaccharide-induced intestinal injury through altering transcriptomic profile

Genistein is abundant in the corn-soybean meal feed. Little information is available about the effect of dietary genistein on the intestinal transcriptome of chicks, especially when suffering from intestinal injury. In this study, 180 one-day-old male ROSS 308 broiler chickens were randomly allocated to 3 groups, with 4 replicates (cages) of 15 birds each. The treatments were as follows: chicks received a basal diet (CON), a basal diet and underwent lipopolysaccharide-challenge (LPS), or a basal diet supplemented with 40 mg/kg genistein and underwent LPS-challenge (GEN). LPS injection induced intestinal injury and inflammatory reactions in the chicks. Transcriptomic analysis identified 7,131 differently expressed genes (3,281 upregulated and 3,851 downregulated) in the GEN group compared with the LPS group (P adjusted value < 0.05, |fold change| > 1.5), which revealed that dietary genistein exposure altered the gene expression profile and signaling pathways in the ileum of LPS-treated chicks. Furthermore, dietary genistein improved intestinal morphology, mucosal immune function, tight junction, antioxidant activity, apoptotic process, and growth performance, which were adversely damaged by LPS injection. Therefore, adding genistein into the diet of chicks can alter RNA expression profile and ameliorate intestinal injury in LPS-challenged chicks, thereby improving the growth performance of chicks with intestinal injury.

Untargeted Metabolite Profiling of Antimicrobial Compounds in the Brown Film of Lentinula edodes Mycelium via LC-MS/MS Analysis

The brown film (BF) of Lentinula edodes mycelium has been reported to exert biological activities during mushroom cultivation; however, to date, there is limited information on its chemical composition. In this study, untargeted metabolomics analysis was performed via liquid chromatography-mass spectrometry (LC-MS), and the results were used to screen the antimicrobial compounds. A total of 236 differential metabolites were found among the BF stages compared with the white hyphal stage. Among them, five important antimicrobial metabolites related to antimicrobial activities, namely, 6-deoxyerythronolide B, tanikolide, hydroxyanthraquinone, benzylideneacetone, and 9-OxooTrE, were present at high levels in the BF samples. The score plots of the principal component analysis indicated that the samples from four time points could be classified into two groups. This study provided a comprehensive profile of the antimicrobial compounds produced during BF formation and partly clarified the antibacterial and antifungal mechanism of the BF of L. edodes mycelium.

The Epigenetic Connection Between the Gut Microbiome in Obesity and Diabetes

Metabolic diseases are becoming an alarming health issue due to elevated incidences of these diseases over the past few decades. Various environmental factors are associated with a number of metabolic diseases and often play a crucial role in this process. Amongst the factors, diet is the most important factor that can regulate these diseases via modulation of the gut microbiome. The gut microbiome participates in multiple metabolic processes in the human body and is mainly responsible for regulation of host metabolism. The alterations in function and composition of the gut microbiota have been known to be involved in the pathogenesis of metabolic diseases via induction of epigenetic changes such as DNA methylation, histone modifications and regulation by noncoding RNAs. These induced epigenetic modifications can also be regulated by metabolites produced by the gut microbiota including short-chain fatty acids, folates, biotin and trimethylamine-N-oxide. In addition, studies have elucidated the potential role of these microbial-produced metabolites in the pathophysiology of obesity and diabetes. Hence, this review focuses on the interactions between the gut microbiome and epigenetic processes in the regulation and development of obesity and diabetes, which may have potential as a novel preventive or therapeutic approach for several metabolic and other human diseases.

Holly polyphenols alleviate intestinal inflammation and alter microbiota composition in lipopolysaccharide-challenged pigs

The effect of holly polyphenols (HP) on intestinal inflammation and microbiota composition was evaluated in a piglet model of lipopolysaccharide (LPS)-induced intestinal injury. A total of twenty-four piglets were used in a 2 × 2 factorial design including diet type and LPS challenge. After 16 d of feeding with a basal diet supplemented with or without 250 mg/kg HP, pigs were challenged with LPS (100 μg/kg body weight) or an equal volume of saline for 4 h, followed by analysis of disaccharidase activities, gene expression levels of several representative tight junction proteins and inflammatory mediators, the SCFA concentrations and microbiota composition in intestinal contents as well as proinflammatory cytokine levels in plasma. Our results indicated that HP enhanced intestinal disaccharidase activities and reduced plasma proinflammatory cytokines including TNF-α and IL-6 in LPS-challenged piglets. Moreover, HP up-regulated mRNA expression of intestinal tight junction proteins such as claudin-1 and occludin. In addition, bacterial 16S rRNA gene sequencing showed that HP altered hindgut microbiota composition by enriching Prevotella and enhancing SCFA production following LPS challenge. These results collectively suggest that HP is capable of alleviating LPS-triggered intestinal injury by improving intestinal disaccharidase activities, barrier function and SCFA production, while reducing intestinal inflammation.

Anti-inflammatory activity of a water-soluble polysaccharide from the roots of purple sweet potato

In this study, a water-soluble polysaccharide was isolated from purple sweet potato roots. The in vitro and in vivo anti-inflammatory effects of the polysaccharide were evaluated by lipopolysaccharide (LPS)-induced inflammatory RAW264.7 macrophages and mice, respectively. The in vitro anti-inflammatory assay showed that the polysaccharide could effectively inhibit the overproduction of nitric oxide and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) while increasing the secretion of anti-inflammatory cytokine (IL-10). The in vivo anti-inflammatory assay revealed that mice administered with the polysaccharide showed higher IL-10, SOD, and T-AOC levels but lower TNF-α, IL-1β, IL-6 and MDA levels as compared to the LPS-treated model. Meanwhile, mice administered with the polysaccharide showed increased abundance of Lachnospiraceae, Lactobacillales and Parabacteroides but decreased amounts of Psychrobacter and Staphylococcus as compared to the LPS model group. Moreover, mice administered with polysaccharide showed enhanced production of short chain fatty acids by gut microbiota in the lipopolysaccharide-induced inflammatory mice. Our results suggested that the water-soluble polysaccharide from purple sweet potato roots could be utilized as a novel anti-inflammatory agent.

A water-soluble polysaccharide from purple sweet potato roots played anti-inflammatory roles by regulating inflammatory cytokines, gut microbiota and antioxidant defense system.

Effects of astragalus and ginseng polysaccharides on growth performance, immune function and intestinal barrier in weaned piglets challenged with lipopolysaccharide

This experiment was conducted to evaluate the effects of astragalus polysaccharides (Aps) and ginseng polysaccharide (Gps) on growth performance, liver function, immune function, TLR4 signalling pathways and intestinal barrier in weaned piglets challenged with lipopolysaccharide (LPS). In an experiment spanning 28 days, 180 weaned piglets were randomly divided into three treatment groups: basal diet (Con), basal diet supplemented with 800 mg/kg Gps (Gps) and basal diet supplemented with 800 mg/kg Aps (Aps). At the end of the experiment, 12 piglets of each group were selected; half (n = 6) were intraperitoneally injected with LPS and half with normal saline. Dietary supplementation with Aps and Gps significantly increased (p < .05) the average daily gain and feed conversion rate. Lipopolysaccharide challenge increased (p < .05) expression of serum urea nitrogen (BUN), alanine aminotransferase (ALT), aspartate aminotransferase (AST), interleukin-1β (IL-1β) and tumour inflammatory factor-α (TNF-α), but decreased (p < .05) serum superoxide dismutase (SOD) level, total antioxidant capacity (T-AOC) and immunoglobulin A (IgA) expression. Lipopolysaccharide-challenged piglets fed with Aps or Gps had lower (p < .05) BUN, ALT, AST, IL-1β and TNF-α levels and greater (p < .05) SOD, T-AOC and IgA levels. Lipopolysaccharide challenge increased (p < .05) the expression of TLR4, MyD88 and NF-κB, and LPS-challenged piglets fed diets supplemented with Aps or Gps increased TLR4 and MyD88 and decreased NF-κB expression. Lipopolysaccharide challenge reduced (p < .05) the jejunal villus height, and piglets fed with Aps or Gps had increased (p < .05) jejunal villus height. Supplementation with Aps or Gps enhanced the expression of occludin and claudin in challenged or unchallenged piglets. In conclusion, dietary supplementation with Aps or Gps enhanced piglet growth performance, alleviated liver dysfunction and reduced immunological stress caused by LPS, as well as increased the intestinal barrier function.

Effects of Blidingia sp. Extract on Intestinal Inflammation and Microbiota Composition in LPS-Challenged Mice

Blidingia sp. is a green alga that has spread rapidly in Subei Shoal, China. To explore the potential beneficial effects of Blidingia sp., we investigated the anti-inflammatory activity of its water–methanol extract of Blidingia sp. in a mouse model of lipopolysaccharide (LPS)-induced intestinal inflammation. The results revealed that the administration of Blidingia extract significantly alleviated the LPS-induced increase of the inflammatory cytokine content in the serum, as well as latter’s gene expression in the ileum. Moreover, the extract inhibited the phosphorylation of NF-κB and IκBα in LPS-challenged mice. Apart from these changes, the extract also averted intestinal morphology damage(s) and cell apoptosis in mice. Interestingly, the extract also had beneficial effects on the diversity and composition of caecal microbiota in LPS-challenged mice. In conclusion, the results suggested that Blidingia extract had beneficial effects on the recovery of intestinal function by reducing the inflammatory response, improving the maintenance of intestinal morphology, and decreasing cell apoptosis in LPS-induced intestinal inflammation. In addition, the beneficial effects of the extract on caecal microbiota composition may play a role in its anti-inflammatory activity. These results suggested that Blidingia extract could be potentially used in preventing intestinal inflammation.