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The altered circulating bile acids (BAs) modulate gut microbiota, energy metabolism and various physiological functions. BA profiles in liver, serum, ileum and feces of HFD-fed mice were analyzed with normal chow diet (NCD)-fed mice after 16-week feeding. Furthermore, gut microbiota was analyzed and its correlation analysis with BA was performed. The result showed that long-term HFD feeding significantly decreased hepatic and serum BA levels, mainly attributed to the inhibition of hepatic BA synthesis and the reduced reabsorption efficiency of BAs in enterohepatic circulation. It also significantly impaired glucose and lipid homeostasis and gut microbiota in mice. We found significantly higher bile salt hydrolase activity in ileal microbes and a higher ratio of free BAs to conjugated BA content in ileal contents in HFD groups compared with NCD group mice, which might account for the activated intestinal farnesoid X receptor signaling on liver BA synthesis inhibition and reduced ileal reabsorption. The decreased circulating BAs were associated with the dysregulation of the lipid metabolism according to the decreased TGR5 signaling in the ileum and BAT. In addition, it is astonishing to find extremely high percentages of taurocholate and 12-OH BAs in liver and serum BA profiles of both groups, which was mainly attributed to the high substrate selectivity for 12-OH BAs of the intestinal BAs transporter during the ileal reabsorption of enterohepatic circulation. This study revealed a significant effect of long-term HFD feeding on the decreased circulating BA pool in mice, which impaired lipid homeostasis and gut microbiota, and collectively resulted in metabolic disorders and obesity. [ABSTRACT FROM AUTHOR]

Sodium benzoate (SB) is a common food preservative widely used in the food industry. However, the effects of SB intake on host health at different stages were still unclear. Hence, we investigated the impact of SB with three concentrations (150 mg/kg, 500 mg/kg and 1000 mg/kg) and at three stages (intake for 5-weeks, intake for 10-weeks and removal for 5 weeks) on host health in normal mice. The results showed that SB intake for 5 weeks slightly changed gut microbiota composition, but it significantly increased TG (only 150 mg/kg and 1000 mg/kg) and blood glucose levels (only 500 mg/kg) and promoted the secretion of interleukin (IL)-1β and IL-6 (p < 0.01). However, SB intake for 10 weeks mostly maintained normal glucolipid metabolism; although, IL-1β (p < 0.01) and IL-6 (p < 0.05) levels were also significantly increased and positively regulated the gut microbiota by significantly increasing the relative abundance of Lactobacillus and significantly decreasing the relative abundance of Ileibacterium. Meanwhile, the safety of SB for host metabolism and gut microbiota was also confirmed via a fecal microbiota transplantation experiment. In addition, we found that SB removal after 10 weeks of intake significantly increased the levels of blood glucose, insulin and HOMA-IR index, which might be attributed to gut microbiota dysbiosis. Mechanistically, these positive effects and negative effects had no close relationship with the concentration of short-chain fatty acids in the gut, which might be associated with metabolites of SB or special bacterial strains. In short, this work provided positive evidence for the safety of SB consumption within the recommended range. [ABSTRACT FROM AUTHOR]

Chicken muscle yield and amino acid composition improvements with medium-chain monoglyceride (MG) supplementation were reported by previous studies, but the underlying mechanism was uncertain. This study aimed to decipher chicken amino acid improvements induced by medium-chain monoglycerides in the views of metabolomics, gene expression, and the gut microbiome. Newly hatched chicks (12,000 chicks) were weighed and randomly divided into two flocks, each with six replicates (1000 chicks per replicate), and fed a basal diet (the control group, CON) or a basal diet enriched with 300 mg/kg MG (the treated group, MG). Results demonstrated that MGs significantly increased the chicken flavor and essential and total amino acids. The serum amino acids and derivatives (betaine, l-leucine, l-glutamine, 1-methylhistide), as well as amino acid metabolism pathways in chickens, were enhanced by MG supplementation. Gene expression analysis exhibited that dietary MGs could improve muscle protein synthesis and cell growth via the mTOR/S6K1 pathway. Dietary MGs enhanced the cecal amino acid metabolism by selectively increasing the proportion of genera Lachnospiraceae_NK4A136_group and Bacteroides. Conclusively, the present study demonstrated that dietary MGs improved chicken amino acid composition via increasing both gut amino acid utilization and muscle amino acid deposition. [ABSTRACT FROM AUTHOR]

The roles of medium- and long-chain triacylglycerols (MLCT) on health benefits under high fat diet (HFD) conditions remain in dispute. This study was conducted to investigate the effects of novel LaPLa-rich MLCT on the glycolipid metabolism and gut microbiota in HFD-fed mice when pork fat is half replaced with MLCT and palm stearin (PS). The results showed that although MLCT could increase the body weight in the mouse model, it can improve the energy utilization, regulate the glucose and lipid metabolism, and inhibit the occurrence of inflammation. Furthermore, 16S rRNA gene sequencing of gut microbiota indicated that PS and MLCT affected the overall structure of the gut microbiota to a varying extent and specifically changed the abundance of some operational taxonomic units (OTUs). Moreover, several OTUs belonging to the genera Dorea, Streptococcus, and g_Eryipelotrichaceae had a high correlation with obesity and obesity-related metabolic disorders of the host. Therefore, it can be seen that this new MLCT has different properties and functions from the previous traditional MLCT, and it can better combine the advantages of MLCT, lauric acid, and sn-2 palmitate, as well as the advantages of health function and metabolism. In summary, this study explored the effects of LaPLa-enriched lipids on glycolipid metabolism in mice, providing theoretical support for future studies on the efficacy of different types of conjugated lipids, intending to apply them to industrial production and subsequent development of related products. [ABSTRACT FROM AUTHOR]

Hyperuricemia (HUA) is a metabolic disorder caused by abnormal uric acid (UA) metabolism, which is a complex physiological process involving multiple organs (liver, kidney, and intestine). Although UA metabolism in the liver and kidneys has been elucidated, only a few studies have focused on the process in the intestine. With our growing knowledge of the effects of gut microorganisms on health, the gut microbiota has been identified as a new target for HUA treatment. In this review, the relationship between HUA and the gut microbiota is elucidated, and anti-hyperuricemia mechanisms targeting the intestine are discussed, such as the promotion of purine and UA catabolism by the gut microbiota, increases in UA excretion by the gut microbiota and its metabolites, regulation of UA absorption or secretion in the intestinal tract by certain transporters, and the intestinal inflammatory response to the gut microbiota. Additionally, probiotics (Bifidobacteria and Lactobacilli) and prebiotics (polyphenols, peptides, and phytochemicals) with UA-lowering effects targeting the intestinal tract are summarized, providing reference and guidance for further research. [ABSTRACT FROM AUTHOR]

BACKGROUND: Medium‐chain monoglycerides (MGs) are a group of 1‐monoglycerides of medium‐chain fatty acids with strong antibacterial activity, which may influence the gut microbiota in the diet of broilers. The present study evaluated the effects of mixed MGs on the community and function of gut microbiota in broilers. A total of 528 newly hatched male yellow feathered broiler chicks were weighed and randomly assigned into four groups, including a basal diet (CON), a basal diet containing 300 mg kg−1 MG (MG300), 450 mg kg−1 MG (MG450), or 600 mg kg−1 MG (MG600). RESULTS: The cecal acetic acid, propionic acid, butyric acid, isobutyric acid, isovaleric acid and total short‐chain fatty acid of broilers in the MG‐containing groups were notably increased compared with the CON group. Dietary MG selectively increased the relative abundance of Bifidobacteriaceae, Bacteroides and an unclassified genus of Lachnospiraceae family, but decreased the proportion of an unclassified genus of Barnesiellaceae and a norank genus of Flavobacteriaceae family in the cecum of broilers. Functional prediction revealed that MG supplementation enriched the microbial gene abundance of amino acid metabolism and carbohydrate metabolism, while depleted the gene abundance of fat metabolism and energy metabolism. Moreover, the modulation of gut microbiota by MG supplementation was closely correlated with the alteration of muscle amino acids. CONCLUSION: Dietary MGs altered the gut microbiota community structure and metabolites, and modulated the gene abundance of microbial metabolism pathways in the cecum of broilers, which may further influence the growth performance, nutrient utilization and meat quality of the host. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Hepatoprotective peptides are potential therapeutic substances used for curing and protecting the liver from diseases. In addition to the nutrition value, evidence indicates that these peptides have a potential role in the body's physiological process. Despite wider practicability of these peptides, their molecular structures still need to be further elucidated, to analyze and better understand its mechanism of action. Their structural variations are mainly attributed to their ultimate processing of different hydrolysates. This study summarizes potential sources, production, structure, and sequence of hepatoprotective peptides, specifically emphasizing on their protective mechanism(s) against alcoholic- and non-alcoholic liver disease. This study also describes an interaction between intestinal microbiota and hepatoprotective peptides. Preliminary research indicated that treatment with bioactive peptide promotes the balance of gut microbiota (GM), mitigates liver inflammation in mice, reverses neutrophil phagocytosis in individuals with alcoholic cirrhosis, and improves liver enzyme levels in excessive drinkers. Besides, it describes hepatoprotective peptides mechanism of action on intestinal microbiota. This work intends to add knowledge in the field of peptides and their impact on hepatoprotection. [Display omitted] • Pointed out the main production of hepatoprotective peptides. • Focused on the sequences of hepatoprotective peptides. • Summarized the differences of hepatoprotective mechanism between NAFLD and ALD. • Reviewed the interaction of hepatoprotective peptides with intestinal flora. [ABSTRACT FROM AUTHOR]

Purpose: In previous studies, short-chain fatty acids (SCFAs) have been found to regulate gut microbiota and change gut barrier status, and the potential positive effects of SCFAs on inflammatory bowel disease (IBD), type 1 diabetes mellitus (T1D), and non-alcoholic fatty liver disease (NAFLD) have also been found, but the role of SCFAs in these three diseases is not clear. This review aims to summarize existing evidence on the effects of SCFAs on IBD, T1D, and NHFLD, and correlates them with gut barrier and gut microbiota (gut microbiota barrier). Methods: A literature search in PubMed, Web of Science, Springer, and Wiley Online Library up to October 2020 was conducted for all relevant studies published. Results: This is a retrospective review of 150 applied research articles or reviews. The destruction of gut barrier may promote the development of IBD, T1D, and NAFLD. SCFAs seem to maintain the gut barrier by promoting the growth of intestinal epithelial cells, strengthening the intestinal tight connection, and regulating the activities of gut microbiota and immune cells, which might result possible beneficial effects on the above three diseases at a certain dose. Conclusions: Influencing gut barrier health may be a bridge for SCFAs (especially butyrate) to have positive effects on IBD, T1D, and NAFLD. It is expected that this article can provide new ideas for the subsequent research on the treatment of diseases by SCFAs and help SCFAs be better applied to precise and personalized treatment. [ABSTRACT FROM AUTHOR]

Constipation is a common gastrointestinal problem. This study aimed to identify a combination of prebiotics and wheat peptides (WP) to promote intestinal peristalsis and explore the underlying mechanism. First, we screened four prebiotics (galacto-oligosaccharides (GOS), fructose oligosaccharides (FOS), inulin (IN), and resistant dextrin (RD)) using a zebrafish model and found that GOS was the most synergistic with WP. We then tested the GOS-WP combination in a mouse model of loperamide (Lop)-induced constipation and found that it significantly improved constipation symptoms. Specifically, GOS-WP shortened the first black stool time, increased the number of defecation particles, accelerated small intestinal propulsion rate, and increased fecal water content. GOS-WP also normalized the colonic water transport system by inhibiting colonic AQP4/8 expression. Additionally, GOS-WP reversed Lop-induced morphological damage in the ileum and colon, increased colonic barrier, and reduced inflammation in mice. Furthermore, 16S rRNA gene sequence analysis showed that GOS-WP reversed the gut microbiota structure changes induced by Lop. GOS-WP significantly increased butyric acid and decreased BCFA levels, indicating improved gut health. Our findings suggest that the GOS-WP combination has potential as a novel intervention for constipation relief. This study highlights the potential of combining prebiotics and WP as a therapeutic strategy for constipation. • Among GOS, FOS, IN and RD, GOS and WP had the strongest synergistic effect in promoting intestinal peristalsis. • The GOS to WP ratio of 1:2 was the most effective in promoting intestinal peristalsis in zebrafish model. • The GOS-WP complex (1:2) could relive constipation under mice model. • The GOS-WP complex (1:2) improved the disturbances of intestinal function in constipated mice. • The GOS-WP complex (1:2) recovered the gut microbiota composition in constipated mice. [ABSTRACT FROM AUTHOR]

Recent studies reveal that glycerol monolaurate (GML) is regarded as an effective feed supplement in the production of broilers; however, the underlying mechanism remains unknown. The current study aimed to investigate how GML affected production performance and meat quality in yellow-feathered broilers. A total of 528 chicks were randomly assigned into four groups for a 56-day feeding trial. The control group received a basal diet, and the treated groups fed basal diet containing 300 (GML300), 450 (GML450), and 600 (GML600) mg/kg GML. Results revealed that dietary GML notably increased the average daily feed intake (p < 0.05) and body weight in broilers during 28–56 days of age and improved the duodenum and jejunum morphology. Dietary GML increased the total cholesterol in broilers (p < 0.05), but the hepatic, abdominal, and muscular fat deposition, as well as muscle fatty acids, were not affected. The flavor amino acids and total amino acids in muscle of GML300 and GML 450 groups were notably (p < 0.05) increased. GML supplementation selectively increased the colonization of an unclassified genus of Lachnospiraceae family and Bifidobacteriaceae, which were significantly (p < 0.05) correlated with the increase of muscle amino acids. Meanwhile, dietary GML notably increased short chain fatty acids content and the microbial DNA abundance of carbohydrate, amino acids and lipid metabolism pathway in cecum. These findings demonstrated that dietary GML improved performance, intestinal morphology, and muscle amino acids in broilers mainly by manipulating community, function and metabolites of gut microbiota. Key points: • GML improves performance, muscle composition, and feed efficiency in broilers. • GML alters gut microbiota community, function, and microbial metabolites in broilers. • Improvements of broilers by GML closely associated with gut microbiota alteration. [ABSTRACT FROM AUTHOR]

As it is known to all that the laying rate of commercial laying hens is significantly decreased during the late laying period, paralleled with increased feed conversion rate (FCR) and declined egg quality. However, recent studies demonstrate that reproductive performance as well as egg quality in aged hens can be largely improved by feed supplements. Among them, glycerol monolaurate (GML), a monoglyceride of medium chain fatty acids, is regarded as a promising supplement in poultry production. The aim of this experiment was to evaluate the effect of dietary GML on laying performance, serum biochemical indices, egg quality and gut microbiota in hens during 40–64 weeks of age. A total of 378 (40-week-old) Hy-Line Brown laying hens were randomly assigned into three treatments (21 hens/replicate and 6 replicates/treatment). The control group received a basal diet, and the treated groups fed basal diets containing 150 and 300 mg/kg GML. The results revealed that laying rate (p < 0.05) was significantly increased and the FCR (p < 0.05) was reduced in GML-containing groups compared with the control group. The egg quality (including eggshell thickness and strength) was notably improved by GML supplementation at the later late laying period, and the content of total amino acids and flavor amino acids in the albumen were also increased. Inclusion of 300 mg/kg GML in diet increased the levels of laying-related sex hormones (serum follicle stimulating hormone, luteinizing hormone and estradiol, p < 0.05), serum calcium and lipid (total serum cholesterol, triglycerides and low-density lipoprotein cholesterol, p < 0.05). Moreover, the community and microbial function of gut microbiota were notably altered by GML supplementation. These findings revealed that dietary GML improved the reproductive performance and egg quality mainly by stimulating the sex hormones secretion, serum calcium metabolism and nutrients utilization, which provided us a new approach to simultaneously promote the egg production and improve the egg quality at aged hens. [ABSTRACT FROM AUTHOR]

Potassium sorbate (PS) is a widely used food preservative in the field of food industry. However, the effects of continuous intake and washout period of PS on host health are still unclear. In this study, to investigate long-term effect and after-effect of different concentrations and time points of PS, healthy mice were orally exposed to 150 mg/kg, 500 mg/kg and 1000 mg/kg of PS for 10 weeks, and washout treatment for another 5 weeks, respectively. The results indicated that PS intake for 10 weeks had no obvious effects on organs and adipose tissue, nor did it noteworthily interfere with glucolipid metabolism in the serum. However, it caused inflammatory cell infiltration in the liver, increased serum interleukin (IL)-1β level, changed abundances of gut microbiota but failed to promote the production of short chain fatty acids in the gut. After washout period for 5 weeks, liver inflammation and IL-1β level were decreased, and gut environment developed towards a healthier condition. Specifically, PS washout significantly increased abundance of Lachnospiraceae_NK4A136_group and the production of isobutyric acid. This study confirmed washout period eliminated negative effects from continuous intake of PS, which provided positive evidence for its safety. [Display omitted] • Continuous intake of PS had no significant effect on organic index. • Continuous intake of PS increased IL-1β level in the serum. • PS washout decreased inflammatory cell infiltration in the liver. • PS washout increased the abundance of Lachnospiraceae_NK4A136_group. • PS washout promoted the production of isobutyric acid. [ABSTRACT FROM AUTHOR]

[Display omitted] • GMC significantly ameliorated visceral fat accumulation in HFD-fed mice. • GMC improved systemic inflammation in HFD-fed mice. • GMC modulated gut microbiota dysbiosis with increased beneficial bacteria and promoted SCFAs production. • GMC-induced metabolic improvements were closely related to gut microbiota regulation. • Not all of the food preservatives and emulsifiers would drive gut microbiota dysbiosis. Recent findings imply that great consideration should be given to the potential health risks of food additives on gut microbiota. Glycerol monocaprylate (GMC) is a widely consumed food preservative and emulsifier. Our results indicated that GMC significantly ameliorated visceral fat accumulation and systemic inflammation in high-fat diet (HFD)-fed mice. Furthermore, GMC induced improvements on the composition and function of gut microbiota, resulting in increased beneficial gut bacteria (Bifidobacterium and Lactobacillus) and promoted production of short chain fatty acids. Notably, GMC-induced metabolic amelioration is closely related to the regulation in gut microbiota. Overall, our findings supported that unlike the emulsifiers previously reported to damage intestinal health, GMC performed the potential on attenuating HFD-induced metabolic disorders and gut microbiota dysbiosis, which also refined on the safety evaluation of GMC on gut microbiota. Our findings suggest that when evaluating the safety of food additives with regards to gut microbiota, it is important to take into account the specific characteristics of the additive in question, rather than simply relying on its classification. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fermented sea buckthorn juice (FHJ) displayed better antioxidant and antidiabetic properties in vitro. • FHJ ameliorated diet-induced hyperlipidemia, insulin resistance, oxidative stress, and gut microbiota dysbiosis in vivo. • FHJ could interact with Akkermansia to further attenuate metabolic syndrome. • FHJ increased acetate and butyrate contents in caeca. • Fermentation-triggered metabolomic alterations, especially flavonoids in FHJ, played critical roles in the FHJ-microorganism interactions. To enhance physiological activity and probiotic availability of sea buckthorn juice, sea buckthorn juice pulp (BHJ) went through fermentation to the fermented (FHJ). In vitro , FHJ displayed better antioxidant and antidiabetic capacities. To further study effects of FHJ on diet-induced metabolic syndrome (MS) and possible mechanisms in vivo , C57BL/6 mice were fed on BHJ and FHJ under high fat diet (HFD). FHJ, rather BHJ, displayed better performance on ameliorating hyperlipidemia, insulin resistance, and oxidative stress in MS. Mechanistically, FHJ intervention significantly reversed the microorganism dysbiosis by restoring the microbial diversity, and modulating obesogenic bacteria abundance, like Oscillospira. Furthermore, fermentation altered FHJ's metabolomics, especially flavonoids, contributing to interactions between FHJ and probiotics, like Akkermansia and Lachnospiraceae. Furthermore, short-chain fatty acids, related to ameliorations of MS, were increased by FHJ. This study demonstrated that interactions between metabolomic alterations in FHJ and microorganisms were vital to attenuate MS. [ABSTRACT FROM AUTHOR]

[Display omitted] • LA, GML and GTL ameliorated HFD-induced hyperlipidemia. • GML performed better effects on glucose metabolism and systemic inflammation. • LA and its glycerides-induced improvements were related to gut microbiota regulation. • GML regulated phospholipid metabolism and gut microbe-related metabolites. • GML promoted endogenous unsaturated fatty acids synthesis. The anti-bacterial properties of lauric acid (LA) and its glycerides had been studied. However, their effects on gut microbiota remain unclear. Moreover, LA and its glycerides performed controversial influences on lipid metabolism. This study evaluated the regulation of LA, glycerol monolaurate (GML) and lauric triglyceride (GTL) on metabolic health and gut microbiota in high fat diet-fed mice. Serum metabolomics and lipidomics contributed to elucidate the underlying mechanisms. LA and its glycerides ameliorated hyperlipidemia, while GML performed more pronounced modulation on glucose metabolism and inflammation. LA and its glycerides modulated gut microbiota with increased Bifidobacterium and decreased Desulfovibrio , which closely related with metabolic improvements. Furthermore, the integrative multi-omics analyses identified that the regulation of phospholipid metabolism, intestinal microbial metabolites (bile acids and indole derivatives) and endogenous unsaturated fatty acids synthesis conduced to the more evident modulation of GML. Our findings suggested an effective strategy of GML for improving metabolism and gut health. [ABSTRACT FROM AUTHOR]