Impact of food-derived bioactive peptides on gut function and health

Soybean Sprout Peptides Alleviate Obesity via PI3K-Akt and JAK-STAT Pathway Modulation, Gut Microbiota Regulation, and Metabolic Reprogramming

Obesity is a growing global health concern associated with severe metabolic disorders, necessitating the development of safer and more effective therapeutic strategies. Soybean sprout peptides (SSPs), derived from germinated soybeans, are bioactive compounds with potential antiobesity effects. This study aimed to investigate the molecular mechanisms of SSPs through an integrated approach combining network pharmacology, molecular docking, and in vivo experiments. SSP sequences were identified using UPLC-Orbitrap-MS/MS, and their bioactivity was predicted using PeptideRanker. Network pharmacology identified key SSP targets, including AKT1, SRC, STAT3, ESR1, FOS, and NFKB1, which are implicated in the PI3K-Akt and JAK-STAT pathways. Molecular docking validated strong interactions between SSPs and these targets. In vivo, SSP administration significantly reduced body weight gain, abdominal fat accumulation, and serum lipid abnormalities in high-fat-diet-induced obese mice while modulating gut microbiota composition by restoring the Firmicutes-to-Bacteroidetes ratio and reducing pathogenic taxa. Fecal metabolomics revealed that SSP alleviated oxidative stress and improved amino acid metabolism, contributing to its antiobesity effects. These findings suggest that SSP holds promise as a functional food ingredient or nutraceutical for obesity prevention and management.

Antihypertensive effects of rice peptides involve intestinal microbiome alterations and intestinal inflammation alleviation in spontaneously hypertensive rats

Gut dysbiosis serves as an underlying risk factor for the development of hypertension. The resolution of this dysbiosis has emerged as a promising strategy in improving hypertension. Food-derived bioactive protein peptides have become increasingly more attractive in ameliorating hypertension, primarily due to their anti-inflammatory and anti-oxidant activities. However, the regulatory mechanisms linking rice peptides (RP), gut dysbiosis, and hypertension remain to be fully elucidated. In our study, male spontaneously hypertensive rats (SHR) were fed with chow diet and concomitantly treated with ddH2O (Ctrl) or varying doses of rice peptides (20, 100, or 500 mg (kg bw day)-1 designated as low-dose RP, LRP; medium-dose RP, MRP; high-dose RP, HAP) or captopril (Cap) by intragastric administration. Wistar-Kyoto (WKY) rats served as the normotensive control group and were orally administered with ddH2O. We observed beneficial effects of RP in lowering blood pressure and ameliorating cardiovascular risk profiles, as evidenced by improvements in glucolipid metabolic disorders, hepatic and renal damage, left ventricular hypertrophy and endothelial dysfunction in hypertensive rats. More importantly, we found that RP attenuated intestinal pathological damage, improved impaired intestinal barrier, and reduced intestinal inflammation by inhibiting the HMGB1-TLR4-NF-κB pathway. Notably, multi-omics integrative analyses have revealed that RP altered the composition and function of the gut microbiota. This is exemplified by the observed enrichment of beneficial bacterial constituents, such as g_Lactobacillus, g_Lactococcus, s_Lactobacillus_intestinalis, and Lactococcus lactis, and elevated production of microbiota-derived short-chain fatty acid metabolites. Collectively, these studies suggest that the hypotensive effects of RP may be associated with modulation of the gut microbiota and its short-chain fatty acids metabolites. This implicates the microbiota-gut-HMGB1-TLR4-NF-κB axis as a novel venue for the amelioration of hypertension and its complications.

Cow Placenta Peptides Ameliorate D-Galactose-Induced Intestinal Barrier Damage by Regulating TLR/NF-κB Pathway

This study investigated the protective effects and mechanisms of cow placenta peptides (CPP) on intestinal barrier damage in aging model mice. Forty-eight male ICR mice were assigned to four groups: a control group (N), an aging model group (M), a CPP treatment group (T), and a vitamin C treatment group (P). Groups T and P received oral administration of CPP (2000 mg/kg/day) and vitamin C (100 mg/kg/day), respectively, while groups M, T, and P were subjected to intraperitoneal injections of D-galactose (D-gal) (300 mg/kg/day). Group N received an equivalent volume of normal saline via intraperitoneal injection. Treatments were administered once daily for 8 weeks. The results demonstrated that CPP significantly alleviated D-galactose-induced intestinal structural damage, increasing the villus height-to-crypt depth ratio and reducing serum diamine oxidase (DAO) and lipopolysaccharide (LPS) levels. CPP notably alleviated intestinal oxidative stress and inflammation, restored tight junction expression, and enhanced intestinal barrier integrity. Transcriptome sequencing identified 1396 DEGs associated with CPP's effects, highlighting TLR4, IL-1β, and Mmp9 as core regulatory genes through protein-protein interaction network analysis. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analyses implicated the TLR4/NF-κB signaling pathway, which was further validated. Western blotting confirmed that CPP significantly down-regulated TLR4, IKKβ, and p-NF-κB p65 protein expression in the intestines of aging mice. In conclusion, CPP effectively alleviates D-gal-induced intestinal barrier damage in aging mice by enhancing antioxidant defense and inhibiting the TLR4/NF-κB signaling pathway, thereby diminishing inflammation and protecting intestinal barrier integrity.

Immunomodulatory activity and molecular mechanisms of action of peptides derived from casein hydrolysate by alcalase and flavourzyme based on virtual screening

This study aimed to screen novel immunomodulatory peptides from casein hydrolysates (CH) using alcalase and flavorzyme by virtual screening, and their molecular mechanism were further studied. Based on the primary structural characteristics of immunomodulatory peptides, along with their hydrophobicity and isoelectric point, 3 novel immunomodulatory peptides (ALPMHIR, AMKPWIQPK, NPWDQVKR) were quickly found using virtual screening. These peptides exhibited strong interactions with TLR2/TLR4 through hydrogen bonding and hydrophobic interactions. Molecular docking verified that the key binding sites, such as Ile733, Ala732, and Phe774 in TLR2/TLR4 contributed to docking. Interestingly, the peptide AMKPWIQPK exhibited the strongest immunomodulatory activity and anti-inflammatory activity as 2-way immunomodulatory peptides. Based on western blot analysis and validation using specific inhibitors against MAPK/NF-κB signaling pathways, the results demonstrated that AMKPWIQPK could recognize the TLR2 and TLR4 receptor of the macrophages to upregulate the phospho-IκBα, phospho-p38, and phospho-p65, and further activated the MAPKs/NF-κB signaling pathways to enhance the immunomodulatory activity. These results confirmed that screening and optimizing immunomodulatory peptides by virtual screening and molecular docking were a novel and rapidly feasible method. The peptide AMKPWIQPK was expected to be used as natural-derived immunomodulatory active ingredients in nutritional health care and functional foods.

Use of pH-sensitive microcapsules for selective delivery of nanozymes and biological enzymes in small intestine

Unlike the intravenous route, oral delivery systems face challenges due to an acidic gastric environment, which can degrade or inactivate therapeutic compounds before they reach the small intestine (SI). Therefore, developing oral delivery strategies that protect cargo from acidic environments and release the content in the SI is imperative. Herein, a novel approach utilizes the pH-sensitivity of alginate-based microcapsules that degrade and release the contents at pH ≥ 7.0. The microcapsules were used to encapsulate gold nanoparticles (AuNPs, a model nanozyme) of varying sizes (2, 15, and 70 nm) and horseradish peroxidase (HRP, a model enzyme). The AuNPs- and HRP-loaded microcapsules (AuNPs-MCap and HRP-PEG MCap) were unaffected at acidic pH (2.0-6.0), as the intrinsic structure and properties of encapsulated AuNPs and HRP were intact. The microcapsules rapidly released the encapsulated AuNPs and HRP at pH ≥ 7.0. In vivo, oral administration of AuNPs-MCap and HRP-PEG MCap to Wistar rats also showed significantly enhanced absorption of AuNPs and HRP in SI, leading to higher concentrations in blood than in their corresponding unencapsulated forms. Overall, the results underscore the potential of pH-responsive microcapsules for protecting pH-sensitive nanozymes, biological enzymes and other bioactive compounds from the acidic gastric environment and for effective and targeted delivery to the SI.

Augmenting Cognitive Function in the Elderly with Mild Cognitive Impairment Using Probiotic Lacticaseibacillus rhamnosus CBT-LR5: A 12-Week Randomized, Double-Blind, Parallel-Group Non-Comparative Study

BACKGROUND

Probiotics have been shown to enhance cognitive function in individuals with mild cognitive impairment (MCI), but their efficacy varies, depending on the strain and dosage.

OBJECTIVES

Clinical investigations are crucial to confirm their safety, efficacy, and mechanism of action. This study was designed to assess the effective dosage, safety, and efficacy of MH-Pro, a test product containing Lacticaseibacillus rhamnosus CBT-LR5 (LR5) and skim milk (non-fat dry milk), in improving cognitive function and related physiological changes in older adults suspected of MCI over 12 weeks.

METHODS

In total, 20 participants (mean age: 68.9 years) were randomly assigned in a 1:1 ratio to either a low-dose group (1 × 1010 CFU LR5 with 1622 mg) or a high-dose group (1 × 1010 CFU LR5 with 4055 mg skim milk) in a double-blind, parallel-group clinical trial.

RESULTS

After 12 weeks, the low-dose group showed significant improvements in the MOCA-K subdomains, specifically in naming (p = 0.01) and delayed recall (p = 0.003). Additionally, levels of amyloid-β1 40/42 in the blood significantly decreased (p = 0.03) following supplementation in the low-dose group. The high-dose group exhibited significant improvement in orientation (p = 0.05). Moreover, overall cognitive enhancement was observed in the low-dose group (p = 0.003), while the high-dose group showed a trend toward improvement (p = 0.06). Fecal analysis revealed significant changes in bacterial composition, with an increase in Lacticaseibacillus after 12 weeks of MH-Pro consumption. Together, these findings provide foundational evidence suggesting that MH-Pro supplementation may serve as a potential intervention for enhancing cognitive function through gut-brain axis pathways in the elderly population. However, given the small sample size and the predominance of female participants, the impact of the outcome may be limited. Further large-scale studies are necessary to validate these preliminary results.

CONCLUSIONS

This study provides foundational evidence to recognize the use of LR5 and skim milk to prepare a probiotic supplement that enhances cognitive function in the aging population.

Food bioactive peptides: functionality beyond bitterness

Bitter taste is an aversive taste because it is unconsciously associated with toxic compounds. However, a considerable variability in bitter sensitivity exists in those who have the genetic polymorphism for bitter taste receptors (TAS2Rs). Besides the oral cavity, TAS2Rs are present in many body tissues, including the gastrointestinal tract; therefore, they are crucial players both in the gustatory/hedonic system and in the homeostatic system, triggering numerous biological responses, including adipogenesis, carcinogenesis, or immunity. Bitter-tasting compounds are widely distributed in plant and animal foods and belong to many chemical classes. In this study, the evidence was reviewed on bitter peptides, considering the food sources, their formation in food under different processing and storage conditions and in the gastrointestinal tract during digestion, as well as their biological activities. Bitterness associated with peptides is due to the presence of hydrophobic amino acids in the C-terminus. The current literature mainly explores the enzymes and hydrolysis conditions, with the aim of reducing the formation of bitter peptides in hydrolysate preparation or food. Few studies highlight the bioactivity (namely, antihypertensive, antidiabetic, antioxidant, or immunity boosting), besides the bitterness. However, encapsulation of bitter peptides has been tentatively used to develop antihypertensive and antidiabetic supplements. In the era of personalized nutrition and precision medicine, the evidence available suggests the opportunity to use bitter bioactive peptides as functional ingredients in food. Such types of food may modulate a plethora of physiological mechanisms by targeting TAS2Rs in the gastrointestinal tract, thus modulating appetite sensations or gastrointestinal motility and discomfort according to individual nutritional needs and goals. More studies are needed to optimize the technological strategies to target TAS2Rs by bitter bioactive peptides, improve their stability in food, and validate the biological efficacy through well-designed in vivo studies.

Natural anti-adhesive components against pathogenic bacterial adhesion and infection in gastrointestinal tract: case studies of Helicobacter pylori, Salmonella enterica, Clostridium difficile, and diarrheagenic Escherichia coli

Antimicrobial resistance (AMR) poses a global public health concern. Recognizing the critical role of bacterial adhesion in pathogenesis of infection, anti-adhesive therapy emerges as a promising approach to impede initial bacterial attachment, thus preventing pathogenic colonization and infection. Natural anti-adhesive agents derived from food sources are generally safe and have the potential to inhibit the emergence of resistant bacteria. This comprehensive review explored diverse natural dietary components exhibiting anti-adhesive activities against several model enteric pathogens, including Helicobacter pylori, Salmonella enterica, Clostridium difficile, and three key diarrheagenic Escherichia coli (i.e., enterotoxigenic E. coli, enteropathogenic E. coli, and enterohemorrhagic E. coli). Investigating various anti-adhesive products will advance our understanding of current research of the field and inspire further development of these agents as potential nutraceuticals or adjuvants to improve the efficacy of conventional antibiotics.

Surfactin from Bacillus subtilis enhances immune response and contributes to the maintenance of intestinal microbial homeostasis

Surfactin, a lipopeptide biosurfactant produced by Bacillus spp., has emerged as a promising bioactive compound due to its potent inhibitory effects on bacterial and viral pathogens. This showcases its potential as a non-antibiotic strategy for managing infectious diseases. Our investigation reveals that surfactin administration significantly promotes weight gain and improves immune organ indices in mice, reflecting enhanced immunity and gut health. Surfactin augments phagocytic function in peritoneal macrophages and boosts proliferative responses in splenic lymphocytes post-chicken red blood cell immunization. Furthermore, it increases intestinal villi height, indicative of superior nutrient absorption. It elevates mucin secretion and expression of intestinal mucosal proteins, such as secretory IgA, Muc1, and Muc2, and tight junction proteins claudin-1, occludin, and Zo-1 in the jejunum and colon. Crucially, surfactin modifies the gut microbiota composition by reducing Escherichia coli populations and ameliorating cyclophosphamide-induced gut dysbiosis. Our data suggest that oral surfactin could be a valuable therapeutic modality to alleviate immune suppression and gut damage, proposing a new pathway for immunomodulatory treatment.

IMPORTANCE

The potential of surfactin as a microbial surfactant extends beyond its surfactant properties, impacting immune regulation and gut health. As the need for alternatives to traditional antibiotics continues to grow, surfactin's ability to enhance host defense mechanisms against common pathogens without directly targeting them with antibiotics offers a strategic advantage. Understanding how surfactin shapes the immune landscape and the gut microbiome can inform innovative interventions against immunosuppression and intestinal impairment, particularly in contexts such as cyclophosphamide-induced toxicity.

Proteins and Peptides from Food Sources with Effect on Satiety and Their Role as Anti-Obesity Agents: A Narrative Review

BACKGROUND/OBJECTIVE

Obesity, clinically defined as a body mass index (BMI) of 30 kg/m2 or higher, is a medical condition characterized by the excessive accumulation of body fat, which can lead to adverse health consequences. As a global public health issue with an escalating prevalence, controlling appetite and satiety is essential for regulating energy balance and managing body weight. Dietary proteins and peptides have gained interest in their potential to prevent and treat obesity by modulating satiety signals. This narrative review analyzes scientific evidence highlighting the role of dietary proteins and peptides in regulating satiety signals and investigates their therapeutic potential in preventing and treating obesity.

METHODS

A comprehensive literature search was conducted in multiple electronic databases, including PubMed, Scopus, and Web of Science. The search focused on articles examining the impact of dietary proteins and peptides on satiety and obesity, encompassing both preclinical and clinical trials.

RESULTS

Several studies have demonstrated a correlation between the intake of specific proteins or peptides from plant and animal sources and satiety regulation. These investigations identified mechanisms where amino acids and peptides interact with enteroendocrine cell receptors, activating intracellular signaling cascades that promote the release of anorexigenic gut hormones such as cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide YY (PYY). Both in vitro and in vivo assays have shown that these interactions contribute to appetite regulation and the sensation of satiety.

CONCLUSIONS

Using proteins and peptides in the diet may be an effective strategy for regulating appetite and controlling body weight. However, more research-including clinical trials-is needed to understand the underlying mechanisms better and optimize the application of these bioactive compounds in preventing and treating obesity.

Cow Placenta Extract Ameliorates Cyclophosphamide-Induced Intestinal Damage by Enhancing the Intestinal Barrier, Improving Immune Function, and Restoring Intestinal Microbiota

Immunosuppression undermines intestinal barrier integrity. Cow placenta extract (CPE) primarily consists of active peptides with immunomodulatory and antioxidant effects. This study aimed to examine the preventive effect of CPE against intestinal damage induced by cyclophosphamide (Cy) in immunosuppressed mice. Thirty-six mice were randomly allocated into three groups: control group (C), model group (M), and treatment group (CPE). The mice in the CPE group were provided with 1500 mg/kg/day of CPE via gavage. In the last 3 days, mice in the groups M and CPE received intraperitoneal injections of 80 mg/kg/day of Cy. The results showed that CPE improved intestinal barrier function by decreasing serum d-Lactate (D-LA) levels and diamine oxidase (DAO) activity, while elevating the relative expression of Occludin, zonula occludens-1 (ZO-1), and mucin-2 (MUC-2) mRNA. Additionally, CPE improved the immune organ index and elevated the levels of secretory immunoglobulin A (sIgA), superoxide dismutase (SOD), interleukin-1beta (IL-1β), interleukin-4 (IL-4), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) in the intestine, thereby enhancing intestinal mucosal immune function. Furthermore, CPE improved the diversity of intestinal microbiota and increased the abundance of Candidatus_Saccharimonas, Psychrobacter, and Enterorhabdus, which promoted the proper functioning of the intestines. These findings suggest that CPE effectively ameliorates Cy-induced intestinal damage by enhancing the intestinal barrier, improving immune function, and restoring intestinal microbiota.

Dual Role of Probiotic Lactic Acid Bacteria Cultures for Fermentation and Control Pathogenic Bacteria in Fruit-Enriched Fermented Milk

The food industry has been developing new products with health benefits, extended shelf life, and without chemical preservation. Bacteriocin-producing lactic acid bacteria (LAB) strains have been evaluated for food fermentation to prevent contamination and increase shelf life. In this study, potentially probiotic LAB strains, Lactiplantibacillus (Lb.) plantarum ST8Sh, Lacticaseibacillus (Lb.) casei SJRP38, and commercial starter Streptococcus (St.) thermophilus ST080, were evaluated for their production of antimicrobial compounds, lactic acid and enzyme production, carbohydrate assimilation, and susceptibility to antibiotics. The characterization of antimicrobial compounds, the proteolytic activity, and its inhibitory property against Listeria (List.) monocytogenes and Staphylococcus (Staph.) spp. was evaluated in buriti and passion fruit-supplemented fermented milk formulations (FMF) produced with LAB strains. Lb. plantarum ST8Sh was found to inhibit List. monocytogenes through bacteriocin production and produced both L(+) and D(-) lactic acid isomers, while Lb. casei SJRP38 mainly produced L(+) lactic acid. The carbohydrate assimilation profiles were compatible with those usually found in LAB. The potentially probiotic strains were susceptible to streptomycin and tobramycin, while Lb. plantarum ST8Sh was also susceptible to ciprofloxacin. All FMF produced high amounts of L(+) lactic acid and the viability of total lactobacilli remained higher than 8.5 log CFU/mL during monitored storage period. Staph. aureus ATCC 43300 in fermented milk with passion fruit pulp (FMFP) and fermented milk with buriti pulp (FMB), and Staph. epidermidis KACC 13234 in all formulations were completely inhibited after 14 days of storage. The combination of Lb. plantarum ST8Sh and Lb. casei SJRP38 and fruit pulps can provide increased safety and shelf-life for fermented products, and natural food preservation meets the trends of the food market.

Effect of digested chia seed protein on the gut microbiota and colon morphology of mice fed a high-saturated-fat diet

The present study aimed to investigate the effect of digested total protein (DTP) from chia seed on the gut microbiota and morphology of mice fed with a high-fat diet. Forty-four male C57BL/6 mice were divided into 4 groups: AIN (standard diet), HF (high-fat diet), AIN + DTP (standard diet supplemented with 400 mg of digested chia seed protein), and HF + DTP (high-fat diet supplemented with 400 mg of digested chia seed protein) during 8 weeks. Colon morphology, tight junction's gene expression, and gut microbiota composition were evaluated. The consumption of digested chia seed protein (DTP) increased the crypts width, longitudinal and circular muscular layer. Furthermore, the AIN + DTP group enhanced the expression of tight junction proteins, including occludin and claudin, while the AIN + DTP and HF + DTP groups increase the zonula occludens expression. The α-diversity analysis showed a reduction in bacterial dominance in the HF + DTP group. All the experimental groups were grouped in different cluster, showing differences in the microbiota community in the β-diversity analyzes. The Firmicutes/Bacteroidetes ratio did not differ among the groups. The genera Olsenella and Dubosiella were increased in the AIN + DTP group, but the Oscillospiraceae_unclassified was increased in the HF + DTP group. The Alistipes was increased, while the Roseburia and Akkermansia were decreased in the AIN + DTP and HF + DTP groups. Then, the consumption of DTP from chia seed improved the gut microbiota composition and mucosal integrity, counteracting the adverse effects of high-fat diet.

Interplay of Food-Derived Bioactive Peptides with Gut Microbiota: Implications for Health and Disease Management

Bioactive peptides (BPs) are protein fragments with beneficial effects on metabolism, physiology, and diseases. This review focuses on proteolytic BPs, which are produced by the action of gut microbiota on proteins in food and have demonstrated to influence the composition of gut microbes. And gut microbiota are candidate targets of BPs to alleviate oxidative stress, enhance immunity, and control diseases, including diabetes, hypertension, obesity, cancer, and immune and neurodegenerative diseases. Despite promising results, further research is needed to understand the mechanisms underlying the interactions between BPs and gut microbes, and to identify and screen more BPs for industrial applications. Overall, BPs offer potential as therapeutic agents for various diseases through their interactions with gut microbes, highlighting the importance of continued research in this area.

Gastrointestinal digestion of food proteins: Anticancer, antihypertensive, anti-obesity, and immunomodulatory mechanisms of the derived peptides

Food proteins and their peptides play a significant role in the important biological processes and physiological functions of the body. The peptides show diverse biological benefits ranging from anticancer to antihypertensive, anti-obesity, and immunomodulatory, among others. In this review, an overview of food protein digestion in the gastrointestinal tract and the mechanisms involved was presented. As some proteins remain resistant and undigested, the multifarious factors (e.g. protein type and structure, microbial composition, pH levels and redox potential, host factors, etc.) affecting their colonic fermentation, the derived peptides, and amino acids that evade intestinal digestion are thus considered. The section that follows focuses on the mechanisms of the peptides with anticancer, antihypertensive, anti-obesity, and immunomodulatory effects. As further considerations were made, it is concluded that clinical studies targeting a clear understanding of the gastrointestinal stability, bioavailability, and safety of food-based peptides are still warranted.

Alginate Oligosaccharides Enhance Antioxidant Status and Intestinal Health by Modulating the Gut Microbiota in Weaned Piglets

Alginate oligosaccharides (AOSs), which are an attractive feed additive for animal production, exhibit pleiotropic bioactivities. In the present study, we investigated graded doses of AOS-mediated alterations in the physiological responses of piglets by determining the intestinal architecture, barrier function, and microbiota. A total of 144 weaned piglets were allocated into four dietary treatments in a completely random design, which included a control diet (CON) and three treated diets formulated with 250 mg/kg (AOS250), 500 mg/kg (AOS500), and 1000 mg/kg AOS (AOS1000), respectively. The trial was carried out for 28 days. Our results showed that AOS treatment reinforced the intestinal barrier function by increasing the ileal villus height, density, and fold, as well as the expression of tight junction proteins, especially at the dose of 500 mg/kg AOS. Meanwhile, supplementations with AOSs showed positive effects on enhancing antioxidant capacity and alleviating intestinal inflammation by elevating the levels of antioxidant enzymes and inhibiting excessive inflammatory cytokines. The DESeq2 analysis showed that AOS supplementation inhibited the growth of harmful bacteria Helicobacter and Escherichia_Shigella and enhanced the relative abundance of Faecalibacterium and Veillonella. Collectively, these findings suggested that AOSs have beneficial effects on growth performance, antioxidant capacity, and gut health in piglets.

Ovalbumin Hydrolysates Enhance Skeletal Muscle Insulin-Dependent Signaling Pathway in High-Fat Diet-Fed Mice

Egg white hydrolysates (EWH) and ovotransferrin-derived peptides have distinct beneficial effects on glucose metabolism. This research aims to investigate whether ovalbumin hydrolysates (OVAHs), without ovotransferrin can improve insulin signaling pathway in high-fat diet (HFD)-fed mice. Two types of ovalbumin hydrolysates were produced, either using thermoase (OVAT), or thermoase + pepsin (OVATP). Both OVAHs-supplemented groups exhibited lower body weight gain (P < 0.001) and enhanced oral glucose tolerance (P < 0.05) compared with HFD. Moreover, diet supplementation with either hydrolysate increased the insulin-stimulated activation of protein kinase B (AKT) and insulin receptor β (IRβ) (P < 0.0001) in skeletal muscle. In conclusion, OVAHs improved glucose tolerance and insulin-dependent signaling pathway in HFD-fed mice.

Musculus senhousei peptides alleviated alcoholic liver injury via the gut-liver axis

Alcoholic liver injury has become a leading threat to human health, with complicated pathogenesis and limited therapeutic options. Our previous study showed that Musculus senhousei peptides (MSPs) exhibit protective potential against early-stage alcoholic liver injury, although the underlying mechanism is not yet clear. In this study, histopathological analysis, mRNA abundance of injury-associated biomarkers, the gut microbiota, and faecal metabolome were evaluated using a mouse model subjected to acute alcohol exposure, aiming to identify the mechanism by which MSP can alleviate alcoholic hepatotoxicity. The results showed that MSP intervention significantly ameliorated symptoms of liver injury (suppressed serum ALT increment, hepatic lipid accumulation, and neutrophil infiltration in liver tissue), and reversed the abnormal mRNA abundance of biomarkers associated with oxidative stress (iNOS), inflammation (TNF-α, IL-1β, MCP-1, TNF-R1, and TLR4), and apoptosis (Bax and Casp. 3) in the liver. Moreover, MSP improved intestinal barrier function by increasing the expression of tight junction proteins (Claudin-1 and Claudin-3). Further analysis of faecal microbiota and metabolome revealed that MSP promoted the growth of tryptophan-metabolizing bacteria (Clostridiales, Alistipes, and Odoribacter), leading to increased production of indole derivatives (indole-3-lactic acid and N-acetyltryptophan). These results suggested that MSPs may alleviate alcohol-induced liver injury targeting the gut-liver axis, and could be an effective option for the prevention of alcoholic liver injury.

Targeting Nrf2 by bioactive peptides alleviate inflammation: expanding the role of gut microbiota and metabolites

Inflammation is a complex process that usually refers to the general response of the body to the harmful stimuli of various pathogens, tissue damage, or exogenous pollutants. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates cellular defense against oxidative damage and toxicity by expressing genes related to oxidative stress response and drug detoxification. In addition to its antioxidant properties, Nrf2 is involved in many other important physiological processes, including inflammation and metabolism. Nrf2 can bind the promoters of antioxidant genes and upregulates their expressions, which alleviate oxidation-induced inflammation. Nrf2 has been shown to upregulate heme oxygenase-1 expression, which promotes NF-κB activation and is closely related with inflammation. Nrf2, as a key factor in antioxidant response, is closely related to the expressions of pro-inflammatory factors, NF-κB pathway and cell metabolism. Bioactive peptides come from a wide range of sources and have many biological functions. Increasing evidence indicates that bioactive peptides have potential anti-inflammatory activities. This article summarized the sources, absorption and utilization of bioactive peptides and their role in alleviating inflammation via Nrf2 pathway. Bioactive peptides can also regulate gut microbiota and alter metabolites, which regulates the Nrf2 pathway through novel pathway and supplement the anti-inflammatory mechanisms of bioactive peptides. This review provides a reference for further study on the anti-inflammatory effect of bioactive peptides and the development and utilization of functional foods.

Effect of Bioactive Peptides on Gut Microbiota and Their Relations to Human Health

Bioactive peptides derived from both exogenous and endogenous origins have been studied extensively to use their beneficial effects in humans and animals. Bioactive peptides exhibit beneficial bodily functions and contribute to a healthy gastrointestinal system by influencing barrier functions, immune responses, and gut microbiota. Gut microbiota is a diverse microbial community that significantly influences the overall well-being and homeostasis of the body. Factors such as diet, age, lifestyle, medication, and environmental circumstances can affect the composition and diversity of the gut microbiota. The disturbances or imbalances in the gut microbiota have been associated with various health problems. The interplays between bioactive peptides and gut microbiota are not fully understood, but bioactive peptides hold promise as modulators of the gut microbiota to promote gut health. Almost all the bioactive research on human health, including the development of therapeutics and nutritional interventions, uses cell culture, even though their direct biofunctional activities can only occur when absorbed in the intestine and into the blood system. This review focuses on the current understanding of bioactive peptides in gut microbiota and their impact and mechanisms on gut and human health. The novelty of this review lies in its comprehensive analysis of the multifaceted interactions between bioactive peptides and gut microbiota, integrating knowledge from diverse disciplines between microbiology and nutrition. By elucidating the underlying mechanisms and identifying current research gaps, this review offers an outlook on the potential of bioactive peptides in promoting gut health and shaping future therapeutic and nutritional interventions.

Bioactive peptides as a novel strategy to prevent alcoholic liver injury

Alcohol intake has become one of the leading risks to human health and wellness, among which acute and/or chronic alcohol-induced liver injury is a leading threaten, with few therapeutic options other than abstinence. In recent years, studies suggested that certain bioactive peptides from food sources could represent natural and safe alternatives for the prevention of alcoholic liver injury. Hence, this chapter focus on the advanced research on bioactive peptides exerting hepatoprotective activity against alcoholic liver injury. The main sources of protein, strategies for the preparation of hepatoprotective hydrolysates and peptides, underlying mechanisms of peptides on hepatoprotection, and possible structure-activity relationship between peptides and hepatoprotective activity were summarized and discussed, aiming to give a systematic insight into the research progress of hepatoprotective peptides. However, more efforts would be needed to give a clearer insight into the underlying mechanisms and structure-activity relationship before using hepatoprotective peptides as functional food ingredients or dietary supplements.

Gut health benefits and associated systemic effects provided by functional components from the fermentation of natural matrices

Recently, the role of the gut microbiota in metabolic health, immunity, behavioral balance, longevity, and intestine comfort has been the object of several studies from scientific communities. They were encouraged by a growing interest from food industries and consumers toward novel fermented ingredients and formulations with powerful biological effects, such as pre, pro, and postbiotic products. Depending on the selected strains, the operating conditions, the addition of suitable reagents or enzymes, the equipment, and the reactor configurations, functional compounds with high bioactivity, such as short-chain fatty acids, gamma-aminobutyric acid, bioactive peptides, and serotonin, can be enhanced and/or produced through fermentation of several vegetable matrices. Otherwise, their formation can also be promoted directly in the gut after the dietary intake of fermented foods: In this case, fermentation will aim to increase the content of precursor substances, such as indigestible fibers, polyphenols, some amino acids, and resistant starch, which can be potentially metabolized by endogenous gut microorganisms and converted in healthy molecules. This review provides an overview of the main functional components currently investigated in literature and the associated gut health benefits. The current state of the art about fermentation technology as a promising functionalization tool to promote the direct or indirect formation of gut-health-enhancing components was deepened, highlighting the importance of optimizing microorganism selection, system setups, and process conditions according to the target compound of interest. The collected data suggested the possibility of gaining novel functional food ingredients or products rich in functional molecules through fermentation without performing additional extraction and purification stages, which are needed when conventional culture broths are used.

Potential of fermented foods and their metabolites in improving gut microbiota function and lowering gastrointestinal inflammation

Foods prepared using microbial conversion of major and minor food components, which are otherwise known as fermented foods continue to impact human health. The live microorganisms and transformed metabolites can also have a deep influence on the gut microbiota, the multifaceted population of microorganisms dwelling inside the gut play a key role in wellbeing of an individual. The probiotic strains delivered through the consumption of fermented food and other bioactive components such as polyphenolic metabolites, bioactive peptides, short-chain fatty acids and others including those produced via gut microbiota mediated transformations have been proposed to balance the gut microbiota diversity and activity, and also to regulate the inflammation in the gut. However, little is known about such effects and only a handful of fermented foods have been explored to date. We herein review the recent knowledge on the dysbiotic gut microbiota linking to major gut inflammatory diseases. Also, evidences that fermented food consumption modulates the gut microbiota, and its impact on the gut inflammation and inflammatory diseases have been discussed. © 2024 Society of Chemical Industry.

The Gastroprotective Effect of Walnut Peptides: Mechanisms and Impact on Ethanol-Induced Acute Gastric Mucosal Injury in Mice

The objective of this research was to explore the protective impact of walnut peptides (WP) against ethanol-induced acute gastric mucosal injury in mice and to investigate the underlying defense mechanisms. Sixty male BALB-c mice were divided into five groups, and they were orally administered distilled water, walnut peptides (200 and 400 mg/kg bw), and omeprazole (20 mg/kg bw) for 24 days. Acute gastric mucosal injury was then induced with 75% ethanol in all groups of mice except the blank control group. Walnut peptides had significant protective and restorative effects on tissue indices of ethanol-induced gastric mucosal damage, with potential gastric anti-ulcer effects. Walnut peptides significantly inhibited the excessive accumulation of alanine aminotransferase (ALT), aspartate transferase (AST), and malondialdehyde (MDA), while promoting the expression of reduced glutathione (GSH), total antioxidant capacity (T-AOC), glutathione disulfide (GSSG), and mouse epidermal growth factor (EGF). Furthermore, the Western blot analysis results revealed that walnut peptides significantly upregulated the expression of HO-1 and NQO1 proteins in the Nrf2 signaling pathway. The defensive impact of walnut peptides on the gastric mucosa may be achieved by mitigating the excessive generation of lipid peroxides and by boosting cellular antioxidant activity.

Unlocking the potential of low FODMAPs sourdough technology for management of irritable bowel syndrome

Consumption of high FODMAP (Fermentable Oligo-, Di-, and Monosaccharides and Polyols) diet is the leading cause of alteration in the human gut microbiome, thereby, causing irritable bowel syndrome (IBS). Therefore, sourdough technology can be exploited for reduction of FODMAPs in various foods to alleviate the symptoms of IBS. Several microorganisms viz. Pichia fermentans, Lactobacillus fetmentum, Saccharomyces cerevisiae, Torulaspora delbrueckii, Kluyveromyces marxianus etc. have been identified for the production of low FODMAP type II sourdough fermented products. However, more research on regulation of end-product and volatilome profile is required for maximal exploitation of FODMAP-reducing microorganisms. Therefore, the present review is focused on utilisation of lactic acid bacteria and yeasts, alone and in synergy, for the production of low FODMAP sourdough foods. Moreover, the microbial bioprocessing of cereal and non-cereal based low FODMAP fermented sourdough products along with their nutritional and therapeutic benefits have been elaborated. The challenges and future prospects for the production of sourdough fermented low FODMAP foods, thereby, bringing out positive alterations in gut microbiome, have also been discussed.

CRISPR/Cas9 System-Mediated Multi-copy Expression of an Alkaline Serine Protease in Aspergillus niger for the Production of XOD-Inhibitory Peptides

CRISPR/Cas9 system-mediated multi-copy expression of an alkaline serine protease (AoproS8) from Aspergillus oryzae was successfully built in Aspergillus niger. Furthermore, AoproS8 was continuously knocked in the glaA, amyA, and aamy gene loci in A. niger to construct multi-copy expression strains. The yield of the AoproS8 3.0 strain was 2.1 times higher than that of the AoproS8 1.0 strain. Then, a high protease activity of 11,023.2 U/mL with a protein concentration of 10.8 mg/mL was obtained through fed-batch fermentation in a 5 L fermenter. This is the first report on the high-level expression of alkaline serine proteases in A. niger. AoproS8 showed optimal activity at pH 9.0 and 40 °C. It was used for the production of xanthine oxidase (XOD)-inhibitory peptides from eight food processing protein by-products. Among them, the duck hemoglobin hydrolysates showed the highest XOD-inhibitory activity with an IC50 value of 2.39 mg/mL. Thus, our work provides a useful way for efficient expression of proteases in A. niger and high-value utilization of protein by-products.

Sea Cucumber Peptide Alleviates Ulcerative Colitis Induced by Dextran Sulfate Sodium by Alleviating Gut Microbiota Imbalance and Regulating miR-155/SOCS1 Axis in Mice

Sea cucumber peptides have been proven to exhibit a variety of biological activities. Ulcerative colitis (UC) is a chronic disease characterized by diffuse inflammation of the mucosa of the rectum and colon with increasing incidence and long duration, and is difficult to cure. The effect of sea cucumber peptide on UC is currently unknown. In this study, 1.5% dextran sulfate sodium (DSS) was added to the drinking water of mice to induce a UC model, and the daily doses of sea cucumber peptide (SP) solution of 200 mg/kg·BW, 500 mg/kg·BW, and 1000 mg/kg·BW were given to UC mice to detect the relieving effect of SP. The results showed that SP can reduce the disease activity index (DAI) of UC mice induced by DSS and can alleviate colon shortening, intestinal tissue damage, and the loss of intestinal tight junction proteins (Claudin-1, Occludin). SP decreased the spleen index, pro-inflammatory factors (IL-1β, IL-6, TNF-α), and myeloperoxidase (MPO) levels in UC mice. SP can alleviate the imbalance of gut microbiota in UC mice, increase the abundance of the Lachnospiraceae NK4A136 group, Prevotellaceae UCG-001, and Ligilactobacillus, and reduce the abundance of Bacteroides and the Eubacterium rum group, as well as alleviating the decrease in short-chain fatty acid (SCFA) content in the feces of UC mice. Notably, SP inhibited miR-155 expression in the colon tissue of UC mice and increased its target protein, suppressor of cytokine signaling 1 (SOCS1), which acts as an inflammatory inhibitor. In summary, the ameliorative effect of SP on UC may be achieved by improving the imbalance of gut microbiota and regulating the miR-155/SOCS1 axis. This study provides a new idea for developing SP as a nutritional supplement to maintain intestinal health.

Evaluating and comparing tolerance, nutritional quality and bio-functional activity of bovine-plasma, corn and whey proteins, outcomes of a randomized double blind controlled trial

Important considerations in the choice of future sustainable protein sources for human application are tolerance, nutritional quality, and potential health benefits. We evaluated, in a double-blind cross-over intervention trial, tolerance, nutritional quality, and potential health effects of two sustainable protein sources. Thirty-six apparently healthy older adults (age 62.3 ± 7.2yrs, BMI 25 ± 3 kg/m2) received 40 g/day bovine-plasma protein (BP), corn protein (CP) or, as a benchmark, whey protein (WP) for one week with a washout period of one week in-between. In 12 participants, we also determined postprandial amino acid (PAA) uptake kinetics upon consumption of 20 g BP, CP, or WP. Changes in self-reported gastrointestinal complaints and intestinal permeability assessed using a multi-sugar acetylsalicylic acid test did not differ between the interventions. Clear differences in PAA responses were observed after consumption of the different proteins, but clear essential amino acid responses were observed for all proteins. BP consumption resulted in a small but significant increase in blood pressure outcomes, and CP consumption resulted in a small but significant decrease in insulin levels when compared to the other interventions. In conclusion, alternative protein concentrates and isolates studied here can be consumed in relative high quantities without experiencing unwanted GI complaints or gut barrier dysfunction and they can be a good source of essential amino acids. The rise in blood pressure observed during the BP intervention, potentially linked to the elevated salt content of the BP, constitutes a potential health issue. Future studies with longer intervention periods might however be recommended.

Effects of Intra-Amniotic Administration of the Hydrolyzed Protein of Chia (Salvia hispanica L.) and Lacticaseibacillus paracasei on Intestinal Functionality, Morphology, and Bacterial Populations, In Vivo (Gallus gallus)

As a protein source, chia contains high concentrations of bioactive peptides. Probiotics support a healthy digestive tract and immune system. Our study evaluated the effects of the intra-amniotic administration of the hydrolyzed chia protein and the probiotic Lacticaseibacillus paracasei on intestinal bacterial populations, the intestinal barrier, the inflammatory response, and brush border membrane functionality in ovo (Gallus gallus). Fertile broiler (Gallus gallus) eggs (n = 9/group) were divided into 5 groups: (NI) non-injected; (H₂O) 18 MΩ H₂O; (CP) 10 mg/mL hydrolyzed chia protein; (CPP) 10 mg/mL hydrolyzed chia protein + 10⁶ colony-forming unit (CFU) L. paracasei; (P) 10⁶ CFU L. paracasei. The intra-amniotic administration was performed on day 17 of incubation. At hatching (day 21), the animals were euthanized, and the duodenum and cecum content were collected. The probiotic downregulated the gene expression of NF-κβ, increased Lactobacillus and E. coli, and reduced Clostridium populations. The hydrolyzed chia protein downregulated the gene expression of TNF-α, increased OCLN, MUC2, and aminopeptidase, reduced Bifidobacterium, and increased Lactobacillus. The three experimental groups improved in terms of intestinal morphology. The current results suggest that the intra-amniotic administration of the hydrolyzed chia protein or a probiotic promoted positive changes in terms of the intestinal inflammation, barrier, and morphology, improving intestinal health.

The gut odorant receptor and taste receptor make sense of dietary components: A focus on gut hormone secretion

Odorant receptors (ORs) and taste receptors (TRs) are expressed primarily in the nose and tongue in which they transduce electrical signals to the brain. Advances in deciphering the dietary component-sensing mechanisms in the nose and tongue prompted research on the role of gut chemosensory cells. Acting as the pivotal interface between the body and dietary cues, gut cells "smell" and "taste" dietary components and metabolites by taking advantage of chemoreceptors-ORs and TRs, to maintain physiological homeostasis. Here, we reviewed this novel field, highlighting the latest discoveries pertinent to gut ORs and TRs responding to dietary components, their impacts on gut hormone secretion, and the mechanisms involved. Recent studies indicate that gut cells sense dietary components including fatty acid, carbohydrate, and phytochemical by activating relevant ORs, thereby modulating GLP-1, PYY, CCK, and 5-HT secretion. Similarly, gut sweet, umami, and bitter receptors can regulate the gut hormone secretion and maintain homeostasis in response to dietary components. A deeper understanding of the favorable influence of dietary components on gut hormone secretion via gut ORs and TRs, coupled with the facts that gut hormones are involved in diverse physiological or pathophysiological phenomena, may ultimately lead to a promising treatment for various human diseases.

Novel Strategy for Alzheimer’s Disease Treatment through Oral Vaccine Therapy with Amyloid Beta

Alzheimer’s disease (AD) is a neuropathology characterized by progressive cognitive impairment and dementia. The disease is attributed to senile plaques, which are aggregates of amyloid beta (Aβ) outside nerve cells; neurofibrillary tangles, which are filamentous accumulations of phosphorylated tau in nerve cells; and loss of neurons in the brain tissue. Immunization of an AD mouse model with Aβ-eliminated pre-existing senile plaque amyloids and prevented new accumulation. Furthermore, its effect showed that cognitive function can be improved by passive immunity without side effects, such as lymphocyte infiltration in AD model mice treated with vaccine therapy, indicating the possibility of vaccine therapy for AD. Further, considering the possibility of side effects due to direct administration of Aβ, the practical use of the safe oral vaccine, which expressed Aβ in plants, is expected. Indeed, administration of this oral vaccine to Alzheimer’s model mice reduced Aβ accumulation in the brain. Moreover, almost no expression of inflammatory IgG was observed. Therefore, vaccination prior to Aβ accumulation or at an early stage of accumulation may prevent Aβ from causing AD.

Egg White Protein Ovotransferrin-Derived IRW (Ile-Arg-Trp) Inhibits LPS-Induced Barrier Integrity Dysfunction and Inflammation in Caco-2 Cells

Tripeptide IRW derived from egg ovotransferrin was initially identified to be an inhibitor of angiotensin-converting enzyme. Later, IRW has been shown to possess various bioactivities, including anti-inflammatory activity and the ability to suppress colitis development. Nevertheless, its role in protecting intestinal barrier integrity has not been reported. This study aims to investigate the effect of IRW on inhibiting intestinal barrier dysfunction and inflammation in lipopolysaccharide (LPS)-treated Caco-2 cells. Pretreatment with IRW could mitigate the LPS-induced reduction of transepithelial electronic resistance values and decrease the paracellular permeation of differentiated Caco-2 cell monolayers. Meanwhile, IRW restored the expression level and cell surface distribution of the tight junction protein occludin. Furthermore, IRW showed LPS-neutralizing activity and could significantly inhibit LPS-induced activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. In conclusion, our study demonstrated the ability of IRW to prevent LPS-induced intestinal barrier dysfunction and prohibit inflammatory responses.

Rice Protein Peptides Alleviate Dextran Sulfate Sodium-Induced Colitis via the Keap1-Nrf2 Signaling Pathway and Regulating Gut Microbiota

Inflammatory bowel disease (IBD), with increasing incidence, causes a range of gastrointestinal symptoms and brings distress and impact on the health and lives of patients. The aim of this study was to explore the protective effects of industrially produced rice protein peptides (RPP) on dextran sulfate sodium (DSS)-induced acute colitis in mice and the potential mechanisms. The results showed that RPP treatment alleviated the symptoms of colitis in mice, including weight loss, colon shortening, and injury, decreased the level of disease activity index (DAI), regulated the balance of inflammatory factors and oxidation, activated Kelch-like ECH-associating protein 1 (Keap1)-nuclear factor E2-related factor 2 (Nrf2) signaling pathway, regulated the expression of related antioxidant proteases, and promoted the expression of intestinal tight junction proteins. In addition, RPP maintained intestinal mucosal barrier function and alleviated acute colitis caused by DSS treatment in mice by increasing the value of F/B, increasing the relative abundance of beneficial bacteria such as Akkermansia, and regulating the level of short-chain fatty acids. In conclusion, RPP alleviated colitis symptoms through the Keap1-Nrf2 signaling pathway and regulating gut microbiota, which had the potential as dietary supplements or functional foods.

Transepithelial transport and cellular mechanisms of food-derived antioxidant peptides

Considering the involvement of oxidative stress in the etiology of many non-communicable diseases, food-derived antioxidant peptides (FDAPs) are strong candidates for nutraceutical development for disease prevention and management. This paper reviews current evidence on the transepithelial transport and cellular mechanisms of antioxidant activities of FDAPs. Several FDAPs have multiple health benefits such as anti-inflammatory and anti-photoaging activities, in addition to antioxidant properties through which they protect cellular components from oxidative damage. Some FDAPs have been shown to permeate the intestinal epithelium, which could facilitate their bioavailability and physiological bioactivities. Molecular mechanisms of FDAPs include suppression of oxidative stress as evidenced by reduction in intracellular reactive oxygen species production, lipid peroxidation and apoptotic protein activation as well as increase in antioxidant defense mechanisms (enzymatic and non-enzymatic). Since many FDAPs have demonstrated promising antioxidant activity, future investigation should focus on further elucidation of molecular mechanisms and human studies to explore their practical application for the prevention and management of oxidative stress-related diseases.

Sustainable Food Systems: The Case of Functional Compounds towards the Development of Clean Label Food Products

The addition of natural components with functional properties in novel food formulations confers one of the main challenges that the modern food industry is called to face. New EU directives and the global turn to circular economy models are also pressing the agro-industrial sector to adopt cradle-to-cradle approaches for their by-products and waste streams. This review aims to present the concept of “sustainable functional compounds”, emphasizing on some main bioactive compounds that could be recovered or biotechnologically produced from renewable resources. Herein, and in view of their efficient and “greener” production and extraction, emerging technologies, together with their possible advantages or drawbacks, are presented and discussed. Μodern examples of novel, clean label food products that are composed of sustainable functional compounds are summarized. Finally, some action plans towards the establishment of sustainable food systems are suggested.

Rhodotorula benthica culture as an alternative to antibiotics improves growth performance by improving nutrients digestibility and intestinal morphology, and modulating gut microbiota of weaned piglets

The effects of Rhodotorula benthica culture (RBC) and antibiotics (AB) on the growth performance, nutrients digestibility, morphological indicators, and colonic microbiota of weaning piglets were explored. Ninety-six (Duroc × Landrace × Large) weaned piglets (21-day-old) weighing 7.7 ± 0.83 kg, were randomly allocated to 4 dietary treatments. They were fed with basal diet (CON), basal diet + 25 mg/kg bacitracin zinc + 5 mg/kg colistin sulfate (AB), 5 g/kg reduction in soybean meal of basal diet + 5 g/kg RBC (RBC1), or 10 g/kg reduction in soybean meal of basal diet + 10 g/kg RBC (RBC2). The results showed that dietary RBC1 improved the body gain/feed intake (G/F) of weaned piglets than the CON diet, and the RBC2 diet improved the average daily gain and G/F than CON and AB diets from days 15 to 28 (P < 0.05). Supplementation of RBC2 improved the apparent total tract digestibility of dry matter, nitrogen, and gross energy in weaned piglets compared to controls from days 15 to 28 (P < 0.05). Dietary AB, RBC1, and RBC2 enhanced the ileal villus height (VH) and VH/crypt depth (CD), and these two indicators were greater in the RBC2-treated piglets than in the AB- and RBC1-treated piglets (P < 0.05). The activity of serum superoxide dismutase (SOD) was enhanced by dietary AB, RBC1, and RBC2 (P < 0.05). Serum glutathione (GSH) concentration was elevated by dietary RBC1 and RBC2 (P < 0.05). According to 16S rRNA sequence analysis, AB- and RBC2-treated piglets had a higher relative abundance of Firmicutes and Lachnospiraceae in the colon digesta, and more abundant Lactobacillus was found in RBC1-treated piglets, as compared to the CON group. Additionally, RBC2 supplementation increased the α diversity [Chao1, PD-whole-tree, and observed operational taxonomic units (OTUs)] compared to the CON group. Taken together, the dietary RBC improved the growth performance of weaned piglets. In addition, 10 g/kg of RBC2 in the diet achieved better effects on higher ADG, ileal villi morphology, and stronger antioxidant capacity than dietary AB and RBC1 in weaning piglets.

Mucin O-glycan-microbiota axis orchestrates gut homeostasis in a diarrheal pig model

BACKGROUND

Post-weaning diarrhea in piglets reduces growth performance and increases mortality, thereby causing serious economic losses. The intestinal epithelial cells and microbiota reciprocally regulate each other in order to maintain intestinal homeostasis and control inflammation. However, a relative paucity of research has been focused on the host-derived regulatory network that controls mucin O-glycans and thereby changes gut microbiota during diarrhea in infancy. At the development stage just after birth, the ontogeny of intestinal epithelium, immune system, and gut microbiota appear similar in piglets and human infants. Here, we investigated the changes of mucin O-glycans associated with gut microbiota using a diarrheal post-weaned piglet model.

RESULTS

We found that diarrhea disrupted the colonic mucus layer and caused aberrant mucin O-glycans, including reduced acidic glycans and truncated glycans, leading to an impaired gut microenvironment. Subsequently, the onset of diarrhea, changes in microbiota and bacterial translocation, resulting in compromised epithelial barrier integrity, enhanced susceptibility to inflammation, and mild growth faltering. Furthermore, we found the activation of NLRP3 inflammasome complexes in the diarrheal piglets when compared to the healthy counterparts, triggered the release of proinflammatory cytokines IL-1β and IL-18, and diminished autophagosome formation, specifically the defective conversion of LC3A/B I into LC3A/B II and the accumulation of p62. Additionally, selective blocking of the autophagy pathway by 3-MA led to the reduction in goblet cell-specific gene transcript levels in vitro.

CONCLUSIONS

We observed that diarrheal piglets exhibited colonic microbiota dysbiosis and mucosal barrier dysfunction. Our data demonstrated that diarrhea resulted in the activation of inflammasomes and autophagy restriction along with aberrant mucin O-glycans including reduced acidic glycans and truncated glycans. The results suggested the mucin O-glycans-microbiota axis is likely associated with diarrheal pathogenesis. Our study provides novel insights into the pathophysiology of early-weaning-induced diarrheal disease in piglets and potentially understanding of disease mechanisms of diarrhea for human infants. Understanding the molecular pathology and pathogenesis of diarrhea is a prerequisite for the development of novel and effective therapies. Our data suggest that facilitating O-glycan elongation, modifying the microbiota, and developing specific inhibitors to some key inflammasomes could be the options for therapy of diarrhea including human infants. Video abstract.

Identification and analysis of antioxidant peptides from sorghum (Sorghum bicolor L. Moench) on the basis of in vitro simulated gastrointestinal digestion

Sorghum (Sorghum bicolor L. Moench) antioxidant peptides in vitro simulated through continuous gastrointestinal (GI) digestion in comparison with rice (Oryza sativa L.) were identified and functionally analysed. It was demonstrated that the protein digestibility of sorghum and rice increased by 11.27% and 14.10% after GI digestion, respectively. The concentrations of the rice peptides GG14, GG12, SF11, and LQ9 and the sorghum peptide KP9 in the gastrointestinal tract were 0.018, 0.712, 0.548, 0.188, and 0.265 μg mL^-1, respectively. An assay of the scavenging ability showed that the sorghum peptide KP9 had the strongest ABTS-scavenging ability, with an IC₅₀ value of 44.44 mg mL^-1. The rice peptide LQ9 had the strongest DPPH and OH radical scavenging activity, with IC₅₀ values of 10.41 and 25.78 mg mL^-1, respectively. These five selectively synthesized peptides were predicted to be nontoxic and to have good ADMET absorption properties. The results indicated that the sorghum and rice peptides obtained by in vitro digestion were separated and purified with certain antioxidant activities and could be consumed as functional foods to modulate certain chronic diseases.

Consumption of Wheat Peptides Improves Functional Constipation: A Translational Study in Humans and Mice

SCOPE

Wheat peptides (WP) are rich in glutamic acid, glutamine, and other bioactive compounds that may benefit gut function and health. This study aims to evaluate the effects of regular consumption of WP on constipation-induced complications and gut microbiota in humans and mice.

METHODS AND RESULTS

A randomized trial of 49 functional constipation participants was conducted. The weekly amount of spontaneous bowel movements (SBM) increased by 2.09 per week after WP treatment, and by 0.40 per week among the placebo group (PL). Concomitantly, the secondary outcomes showed significant improvements in the quality of life-related to constipation, constipation severity, and satisfaction with the intervention. In the animal study, WP effectively alleviated constipation symptoms and affected the secretion of intestinal mobility-related neurotransmitters and gastrointestinal hormones in loperamide-induced constipation mice. Additionally, WP regulated the gene and protein expression levels of water-electrolyte metabolism and intestinal mobility. Furthermore, WP treatment decreased the abundance of several gut microbiota positively correlated to constipation (Turicibacter, Bacteroides_f_Bacteroidaceae, and Streptococcus) in mice.

CONCLUSION

WP ameliorated constipation in humans and mice, which could be partly explained by improving water-electrolyte metabolism, boosting intestinal motility, and reshaping gut microbiota. This article is protected by copyright. All rights reserved.

Oral delivery of marine shellfish supramolecule peptides for skin wound healing

Oral administration of peptides/proteins with superior efficacy and fewer side effects is the most advantageous route of administration. In this study, we utilized controllable enzymatic (animal protease) hydrolysis technology to prepare active polypeptide self-assembling supramolecular (APs) from marine shellfish meat to explore the functional mechanism of APs in in vitro and in vivo (oral administration) experiments . In vitro experiments revealed that APs with self-assembly tendency had multifunctional activities. In vivo experiments indicated that oral administration of naturally safe APs could inhibited inflammation, promoted fibroblast proliferation and revascularization, and accelerated the epithelialization process, thus favoring a balanced repair tissue collagen I/III ratio and the promotion of hair follicle regeneration to achieve scarless healing, which was also relevant to "skin-gut" axis. These results showed that APs, as demonstrated in this study, promoted dermal wound healing in mice and may be developed and used to treat skin wounds.

Enzymatic hydrolysis and microbial fermentation: The most favorable biotechnological methods for the release of bioactive peptides

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Peptide release methods influence its bioactivity by generating different sequences.

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The absorption, toxicity and taste of peptides is influenced by the production method.

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The most used methods are enzymatic hydrolysis and microbial fermentation.

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The most used methods are biotechnological and differ in their process.

Bioactive peptides are biomolecules derived from proteins. They contain anywhere from 2 to 20 amino acids and have different bioactivities. For example, they have antihypertensive activity, antioxidant activity, antimicrobial activity, etc. However, bioactive peptides are encrypted and inactive in the parental protein, so it is necessary to release them to show their bioactivity. For this, there are different methods, where biotechnological methods are highly favorable, highlighting enzymatic hydrolysis and microbial fermentation.

The choice of the method to be used depends on different factors, which is why it is essential to know about the process, its principle, and its advantages and disadvantages. The process of peptide release is critical to generate various peptide sequences, which will produce different biological effects in the hydrolysate. This review focuses on providing extensive information on the enzymatic method and microbial fermentation to facilitate selecting the method that provides the most benefits.