Supplement of Caulerpa lentillifera polysaccharide by pre-prandial gavage and free feeding demonstrates differences to prevent obesity and gut microbiota disturbance in mice.

BACKGROUND: Caulerpa lentillifera has received extensive attention regarding expansion of its farming and increasing consumption. In our previous study, the structure of C. lentillifera polysaccharide (CLP) was elucidated. However, little information is available about its health effects. In this study, the anti-obesity effect of CLP was investigated by using a high-fat diet-induced obese mice model with two different supplementation methods. RESULTS: In vitro simulated digestion results showed that CLP significantly decreased the lipid digestibility and induced the lipid droplets aggregation in the intestinal stage to inhibit the absorption of lipids. As revealed by 16S ribosomal RNA sequencing and non-targeted metabolomics, supplement of CLP by both pre-prandial gavage and free feeding patterns effectively prevented mice obesity via ameliorating intestinal flora disturbance and regulating bile acids circulation metabolism. Of note was that CLP administration had no effect on short-chain fatty acids production, suggesting the anti-obesity effect was uncorrelated with their production. Moreover, pre-prandial administration of CLP had a better anti-obesity effect in lowering body weight and serum lipid levels, but the free feeding resulted in a higher α-diversity of gut microbiota. CONCLUSION: The findings of this study indicate that CLP could be a potential anti-obesity nutraceutical and that pre-prandial supplement of CLP may be a better intake method to exhibit its hypolipidemic effect. © 2022 Society of Chemical Industry.

Distribution analysis of polysaccharides comprised of uronic acid-hexose/hexosamine repeating units in various shellfish species.

Acidic polysaccharides are attractive functional ingredients in shellfish which are consumed as delicious and nutritious foods world widely. In the present study, acidic polysaccharides from 21 species of edible shellfish were characterized and quantified by analyzing their repeated disaccharides using the multiple reaction monitoring (MRM) mode of triple quadrupole mass spectrometer upon acid degradation and 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization. A total of 6 glycosaminoglycans (GAGs) and 8 non-GAGs with repeated disaccharide units of a hexuronic acid linked to a hexosamine or a hexose were detected. Among them, chondroitin sulfate, heparin, →4)-ß-GlcA-(1 → 2)-α-Man-(1 → and →3)- ß-GlcA-(1 → 3)-α-Gal-(1 → were identified unambiguously by comparing with the references. The quantification results revealed that the contents of these polysaccharide varied greatly among shellfish species with a maximum over 100 mg/100 g. Furthermore, the dendrogram of hierarchical clustering analysis indicated that the composition of acidic polysaccharides in some shellfish species was related with the genetic relationship. Thus, the present study provides a more comprehensive knowledge about the distribution of acidic polysaccharides in various shellfish species.

Quantification and comparison of acidic polysaccharides in edible fish intestines and livers using HPLC-MS/MS.

Fish intestines and livers are usually considered as delicious and nutritious food in China. Acidic polysaccharides are important nutrients in these food of animal origin, but there is currently little information regarding their quantitative distributions. The present study demonstrated a method to quantify acidic polysaccharides simultaneously by analyzing their disaccharides produced from the acid hydrolysis using high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry. The recoveries for these acidic polysaccharides were all 97%-115% with relative standard deviation of 3.0%-9.0%. All of the acidic polysaccharides had good linearities. Then this method was applied to determine the composition of acidic polysaccharides in 5 edible fish livers and intestines. Besides well-known glycosaminoglycans (GAGs) including hyaluronic acid (HA), Chondroitin sulfate (CS), dermatan sulfate (DS) and heparin (HP), 4 novel acidic polysaccharides including 2 GAGs and 2 non-GAGs comprised of hexose-hexuronic acid repeating units were also found. CS and HP were the major acidic polysaccharides components in fish intestines and livers, respectively. The absolute amounts of acidic polysaccharides differed greatly in these fish tissues, but their proportions showed similarity in the same type of tissues. The present study demonstrated an effective method for acidic polysaccharides quantification, and revealed acidic polysaccharides compositions of edible fish livers and intestines.

Mucosal delivery of allergen peptides expressed by Lactococcus lactis inhibit allergic responses in a BALB/c mouse model.

Allergen-specific immunotherapy (SIT) is considered to be the only curative treatment of allergy, but its safety is always affected by immunologic properties and quality of allergen. Recombinant allergen derivative could be a potential therapeutic strategy, but clinical studies showed that macromolecular derivatives could not avoid T cell-mediated side effects. In this study, five Der p2-derived peptides (DPs) containing major T cell epitopes of Der p2 were first artificially synthesized. Compared with Der p2 macromolecular derivative DM, these DPs not only fully eliminated IgE-binding capacity but also reduced T cells reactivity, suggesting these DPs could be better therapeutic molecules. For their application in vivo, Lactococcus lactis was engineered to express these DPs, and their protective effects were evaluated in BALB/c mice models. Western blot showed that all DPs could be produced in the recombinant strains. Mucosal delivery of these strains could inhibit Der p2-induced allergic responses in Der p2-sensitized mice, characterized by a reduction in specific IgE antibody and lung inflammatory responses. These protective effects were associated with an increase of specific IgG2a in serum and regulatory T cells in the mesenteric lymph nodes. On the whole, the suppressive effect induced by the DP mixture could be better than single DP, but a bit weaker than DM. These DPs could be promising candidate molecules for active vaccination and induction of tolerance, and thus promote the development of non-allergenic peptide in the treatment and prevention of allergy.

Suppression of dust mite allergy by mucosal delivery of a hypoallergenic derivative in a mouse model.

Allergic asthma caused by house dust mite (HDM) is becoming a public health problem. Specific immunotherapy is considered to be the only curative treatment, but it is always associated with IgE-mediated side effects in the therapy process. A few studies showed that the disruption of allergen IgE epitopes could reduce IgE reactivity and thus reduce allergenic activity. In this study, a hypoallergenic derivative of the major HDM allergen Der p2 was constructed by genetic engineering. This derivative was confirmed to have a considerably reduced IgE reactivity compared with Der p2. For its application in vivo, recombinant Lactococcus lactis (LL-DM) was engineered to deliver the Der p2 derivative to the intestinal mucosal surface. Oral administration of LL-DM significantly alleviated Der p2-induced airway inflammation, as shown by reduced inflammatory infiltration and a reduction in Th2 cytokines in bronchoalveolar lavage. This protective effect was associated with an up-regulation of specific IgG2a and a decrease in IL-4 level in the spleen which may affect specific IgE response. Moreover, the levels of regulatory T cells in the mesenteric lymph nodes and spleen were markedly increased in mice fed with LL-DM, suggesting that LL-DM can inhibit allergic responses via the induction of regulatory T cell. Our results indicate that the Der p2 derivative is a promising therapeutic molecule for specific immunotherapy and recombinant lactic acid bacteria could be developed as a promising treatment or prevention strategy for allergic diseases.

Modulation of peanut-induced allergic immune responses by oral lactic acid bacteria-based vaccines in mice.

Peanut allergy (PNA) has becoming a non-negligible health concern worldwide. Thus far, allergen-specific immunotherapy aimed at inducing mucosal tolerance has widely been regarded as a major management strategy for PNA. The safety profiles and the intrinsic probiotic properties of lactic acid bacteria (LAB) render them attractive delivery vehicles for mucosal vaccines. In the present study, we exploited genetically modified Lactococcus lactis to produce peanut allergen Ara h 2 via different protein-targeting systems and their immunomodulatory potency for allergic immune responses in mice were investigated. By comparison with the strain expressing the cytoplasmic form of Ara h 2 (LL1), the strains expressing the secreted and anchored forms of Ara h 2 (LL2 and LL3) were more potent in redirecting a Th2-polarized to a non-allergic Th1 immune responses. Induction of SIgA and regulatory T cells were also observed at the local levels by orally administration of recombinant L. lactis. Our results indicate that allergen-producing L. lactis strains modulated allergic immune responses and may be developed as promising mucosal vaccines for managing allergic diseases.

Modulation effect of sulfated polysaccharide from Sargassum fusiforme on gut microbiota and their metabolites in vitro fermentation.

The present study demonstrated the digestion behavior and fermentation characteristics of a sulfated polysaccharide from Sargassum fusiforme (SFSP) in the simulated digestion tract environment. The results showed that the molecular weight of two components in SFSP could not be changed by simulated digestion, and no free monosaccharide was produced. This indicates that most of SFSP can reach the colon as prototypes. During the fermentation with human intestinal flora in vitro, the higher-molecular-weight component of SFSP was utilized, the total sugar content decreased by 16%, the reducing sugar content increased, and the galactose content in monosaccharide composition decreased relatively. This indicates that SFSP can be selectively utilized by human intestinal flora. At the same time, SFSP also changed the structure of intestinal flora. Compared with the blank group, SFSP significantly increased the abundance of Bacteroidetes and decreased the abundance of Firmicutes. At the genus level, the abundances of Bacteroides and Megamonas increased, while the abundances of Shigella, Klebsiella, and Collinsella decreased. Moreover, the concentrations of total short-chain fatty acids (SCFAs), acetic, propionic and n-butyric acids significantly increased compared to the blank group. SFSP could down-regulate the contents of trimethylamine, piperidone and secondary bile acid in fermentation broth. The contents of nicotinic acid, pantothenic acid and other organic acids were increased. Therefore, SFSP shows significant potential to regulate gut microbiota and promote human health.

Orally administrated fucoidan and its low-molecular-weight derivatives are absorbed differentially to alleviate coagulation and thrombosis.

Thrombosis is a serious threat to human health and life. Fucoidan, a sulfated polysaccharide from brown algae, could prevent coagulation and thrombus after intravenous administration. However, more efforts are still needed to develop its oral agent. In the present study, the absorption and excretion of fucoidan (90.8 kDa) and its degradation products, Dfuc1 (19.2 kDa) and Dfuc2 (5.5 kDa), were determined by HPLC-MS/MS after acid degradation and 1-phenyl-3-methyl-5-pyrazolone derivatization, and their anticoagulation and antithrombotic activities were evaluated in vivo after oral administration. Results showed that the maximum concentrations of fucoidan, Dfuc1 and Dfuc2 in rat plasma all achieved at 2 h after oral administration (150 mg/kg), and they were 41.1 ± 10.6 µg/mL, 45.3 ± 18.5 µg/mL and 59.3 ± 13.7 µg/mL, respectively. In addition, fucoidan, Dfuc1 and Dfuc2 could all prolong the activated partial thromboplastin time in vivo from 23.7 ± 2.7 s (blank control) to 25.1 ± 2.6 s, 27.1 ± 1.7 s and 29.4 ± 3.6 s, respectively. Moreover, fucoidan and its degradation products showed similar antithrombotic effect in carrageenan-induced thrombosis mice, and untargeted metabolomics analysis revealed that they all markedly regulated the carrageenan-induced metabolite disorders, especially the arachidonic acid metabolism. Thus, the degradation products of fucoidan with lower molecular weights are more attractive for the development of oral antithrombotic agents.

The protective effect of Enteromorpha prolifera polysaccharide on alcoholic liver injury in C57BL/6 mice.

An alcohol-induced liver injury model was induced in C57BL/6 mice to assess the protective efficacy of Enteromorpha prolifera polysaccharides (EP) against liver damage. Histological alterations in the liver were examined following hematoxylin-eosin (H&E) staining. Biochemical assay kits and ELISA kits were employed to analyze serum and liver biochemical parameters, as well as the activity of antioxidant enzymes and alcohol metabolism-related enzymes. The presence of oxidative stress-related proteins in the liver was detected using western blotting. Liquid chromatography and mass spectrometry were used to profile serum metabolites in mice. The findings demonstrated that EP-H (100 mg/Kg) reduced serum ALT and AST activity by 2.31-fold and 2.32-fold, respectively, when compared to the alcohol-induced liver injury group. H&E staining revealed a significant attenuation of microvesicular steatosis and ballooning pathology in the EP-H group compared to the model group. EP administration was found to enhance alcohol metabolism by regulating metabolite-related enzymes (ADH and ALDH) and decreasing CYP2E1 expression. EP also modulated the Nrf2/HO-1 signaling pathway to bolster hepatic antioxidant capacity. Furthermore, EP restored the levels of lipid metabolites (Glycine, Butanoyl-CoA, and Acetyl-CoA) to normalcy. In summary, EP confers protection to the liver through the regulation of antioxidant activity and lipid metabolites in the murine liver.

Haematococcus pluvialis polysaccharides improve microbiota-driven gut epithelial and vascular barrier and prevent alcoholic steatohepatitis development.

Algal polysaccharides possess many biological activities and health benefits, such as antioxidant, anti-tumor, anti-coagulant, and immunomodulatory potential. Gut microbiota has emerged as one of the major contributor in mediating the health benefits of algal polysaccharides. In this study we showed that Haematococcus pluvialis polysaccharides (HPP) decreased serum transaminase levels and hepatic triglyceride content, alleviated inflammation and oxidative stress in the liver of chronic and binge ethanol diet-fed mice. Furthermore, HPP reduced endotoxemia, improved gut microbiota dysbiosis, inhibited epithelial barrier disruption and gut vascular barrier (GVB) damage in ethanol diet-fed mice. Co-housing vehicle-fed mice with HPP-fed mice alleviated ethanol-induced liver damage and endotoxemia. Moreover, fecal microbiota transplantation from HPP-fed mice into antibiotic-induced microbiota-depleted recipients also alleviated ethanol-induced liver injury and improved gut epithelial and vascular barrier. Our study demonstrated that HPP ameliorated ethanol-induced gut epithelial and vascular barrier dysfunction through alteration of gut microbiota, therefore preventing alcoholic liver damage.

Research Advances of Modification and Nutraceutical Properties of Polysaccharide.

As a group of important biopolymers, polysaccharides exist widely in living organisms and play many known and unknown biological roles in life activities via different pathways [...].

Undaria pinnatifida fucoidan ameliorates dietary fiber deficiency-induced inflammation and lipid abnormality by modulating mucosal microbiota and protecting intestinal barrier integrity.

Dietary fiber deficiency (FD) is a new public health concern, with limited understanding of its impact on host energy requirements and health. In this study, the effect of fucoidan from Undaria pinnatifida (UPF) on FD-induced alterations of host physiological status was analyzed in mice. UPF increased colon length and cecum weight, reduced liver index, and modulated serum lipid metabolism primarily involving glycerophospholipid and linoleic acid metabolism in FD-treated mice. UPF protected against FD-induced destruction of intestinal barrier integrity by upregulating the expression levels of tight junction proteins and mucin-related genes. UPF alleviated FD-induced intestinal inflammation by reducing the levels of inflammation-related factors, such as interleukin-1ß, tumor necrosis factor-α, and lipopolysaccharides, and relieving oxidative stress. The underlying mechanism can be closely associated with modulation of gut microbiota and metabolites, such as a reduction of Proteobacteria and an increase in short chain fatty acids. The in vitro model showed that UPF mitigated H2O2-induced oxidative stress and apoptosis in IEC-6 cells, indicating its potential as a therapeutic agent for inflammatory bowel disorders. This study suggests that UPF can be developed as a fiber supplement to benefit host health by modulating gut microbiota and metabolites and protecting intestinal barrier functions.

Undaria pinnatifida fucoidan contributes to anti-inflammation activity of Bacteroides in fiber-deficient mice via modulation of gut microbiota and protection of intestinal barrier integrity.

Bacteroides as potential probiotics has several health benefits to the host, but its practical application faces many challenges due to its inherent properties. In this study, Bacteroides strains isolated from human feces alleviated colonic inflammation in mice, as evidenced by increased colon length and reduced tissue damage. Further study showed that anti-inflammation activity of Bacteroides strains was disturbed by dietary fiber deficiency (FD), which disrupted the balance between gut microbiota and colonic mucus layer, leading to a thinning of colonic mucus layer. A combination of Bacteroides strains and Undaria pinnatifida fucoidan (UPF) better alleviated colonic inflammation than either of them, including increases in the densities of goblet cells and glycoproteins and reduction in intestinal epithelial damage, pro-inflammatory cytokines and oxidative stress. The underlying mechanisms can be attributed to that UPF-induced alterations of mucosal microbiota cannot only directly benefit host health but also create an ecological condition that facilitates Bacteroides strains exert their healthy properties. In addition, both Bacteroides strains and UPF improved FD-induced lipid metabolism abnormality, mainly involving glycerophospholipid metabolism pathway. This study suggests that the application of Bacteroides has certain limitations, and UPF can be developed as a probiotic adjuvant for Bacteroides to enhance human health.

Scytosiphon lomentaria fucoidan ameliorates DSS-induced colitis in dietary fiber-deficient mice via modulating the gut microbiota and inhibiting the TLR4/NF-κB/MLCK pathway.

The prevalence of ulcerative colitis (UC) poses a serious threat to human health. This study showed that fiber-deficient diet (FD) increased the susceptibility of mice to low dosage of DSS-induced UC, and a UC model was established by feeding mice with DSS and FD to evaluate the effect of Scytosiphon lomentaria fucoidan (SLF) on UC. SLF ameliorated the symptoms of UC, as evidenced by increases in colon length, goblet cells and glycoprotein and reduction in inflammatory cell infiltration and intestinal epithelial injury. SLF alleviated oxidative stress and inhibited colonic inflammation by reducing the levels of lipopolysaccharides and pro-inflammatory cytokines and suppressing the activation of nuclear factor kappa B pathway. SLF protected tight junction integrity by reducing the level of myosin light chain kinase and increasing the levels of claudin, zonula occludens-1 and occludin. SLF improved serum metabolites profile and affected multiple metabolic pathways that are crucial to human health, e.g. butanoate metabolism. The underlying mechanism can be associated with modulation of the gut microbiota and metabolites, including increases in short chain fatty acids and reduction in Proteobacteria, Bacteroides and Romboutsia. It suggests that SLF could be developed as a prebiotic polysaccharide to benefit human health by improving intestinal microecology.

Sea cucumber sulfated polysaccharides and Lactobacillus gasseri synergistically ameliorate the overweight induced by altered gut microbiota in mice.

Sulfated polysaccharides from sea cucumber Stichopus japonicus (SCSPsj) have been found to modulate the gut microbiota by promoting the growth of probiotics. However, the effects of the combination of SCSPsj and probiotics are still less known. Thus, the present study aimed to investigate the effects of SCSPsj and Lactobacillus gasseri on gut microbiota-altered mice through gut microbiota and metabolomics analysis. In the present study, supplementation with SCSPsj, L. gasseri or the combination of SCSPsj and L. gasseri could effectively ameliorate the body weight gain and fat accumulation in gut microbiota-altered mice treated with low-dose penicillin. The better effect of the combination of SCSPsj and L. gasseri is attributed to the synergistic effect of SCSPsj and L. gasseri. 16S rRNA sequencing revealed that the combination of SCSPsj and L. gasseri can synergistically improve gut microbiota dysbiosis by increasing Lactobacillus and reducing Coriobacteriaceae_UCG-002. Furthermore, metabolomics results revealed that the combination of SCSPsj and L. gasseri can alleviate metabolic disorders by reducing the levels of lipid and lipid-like molecules in the serum samples, such as trans-vaccenic acid and 3ß-hydroxy-5-cholestene. Our findings have proved that the combination of SCSPsj and L. gasseri can benefit host health attributed to the synergistic effect, which is conducive to further application in functional food.

Ascophyllum nodosum polysaccharide regulates gut microbiota metabolites to protect against colonic inflammation in mice.

Ascophyllum nodosum polysaccharide (ANP) can protect against colonic inflammation but the underlying mechanism is still unclear. This study has determined the metabolites of gut microbiota regulated by ANP to reveal the mechanism of the anti-inflammation effect of ANP. Using an in vitro colonic fermentation model, the results indicate that gut microbiota could utilize a proportion of ANP to increase the concentrations of short-chain fatty acids (SCFAs) and decrease ammonia content. Metabolomics revealed that 46 differential metabolites, such as betaine, L-carnitine, and aminoimidazole carboxamide ribonucleotide (AICAR), could be altered by ANP. Metabolic pathway analysis showed that ANP mainly up-regulated the phenylalanine, tyrosine, and tryptophan biosynthesis and aminoacyl-tRNA biosynthesis, which were negatively correlated with inflammation progression. Interestingly, these metabolites associated with inflammation were also up-regulated by ANP in colitis mice, including betaine, L-carnitine, AICAR, N-acetyl-glutamine, tryptophan, and valine, which were mainly associated with amino acid metabolism and aminoacyl-tRNA biosynthesis. Furthermore, the metabolites modulated by ANP were associated with the relative abundances of Akkermansia, Bacteroides, Blautia, Coprobacillus, Enterobacter, and Klebsiella. Additionally, based on VIP values, betaine is a key metabolite after the ANP supplement in vitro and in vivo. As indicated by these findings, ANP can up-regulate the production of SCFAs, betaine, L-carnitine, and AICAR and aminoacyl-tRNA biosynthesis to protect against colonic inflammation and maintain intestinal health.

H2O2-TiO2 photocatalytic degradation of chondroitin sulfate and in vivo absorption and excertion of its product.

Chondroitin sulfate (CS) is widely known for its various biological activities which are closely related to the sulfate substitution and the molecular weight. Effective degradation methods without striping sulfate groups are in a need. In the present study, a photocatalytic degradation method using H2O2 and TiO2 has been developed and it could decrease the average molecular weight of CS into 5 kDa within 6 h. The chemical composition of CS before and after degradation were compared by FT-IR, NMR, etc., and no removement of sulfate group was observed. Then the identification of the oligosaccharides in the degradation product by mass spectroscopy revealed that glucuronic acid or its derivative, arabinuronic acid, was at most of the reducing ends, and the depolymerization mechanism was proposed. Furthermore, the absorption of CS in rats was enhanced by the degradation while the excertion profile of the degradation product was similar to that of CS.

Inhibitory effects of fucoidan from Laminaria japonica against some pathogenic bacteria and SARS-CoV-2 depend on its large molecular weight.

Fucoidan is a highly sulfated polysaccharide with a wide range of bioactivities, including anti-pathogenic activity. However, the relationship between structure and activity of fucoidan in inhibiting pathogen infections remains unclear. Here, different-molecular-weight fucoidans were prepared by photocatalytic degradation followed by membrane ultrafiltration, and their chemical structures and anti-pathogenic microbiota activity were compared. Results showed that photocatalytic degradation could effectively degrade fucoidan while its structure block and sulfate groups were not destroyed obviously. Fucoidan (90.8 kDa) of 5 mg/mL could inhibit the growth of S. aureus, S. typhimurium and E. coli, but its degradation products, Dfuc1 (19.2 kDa) and Dfuc2 (5.5 kDa), demonstrated lower inhibitory effect. In addition, compared to Dfuc1 and Dfuc2, fucoidan showed stronger capability to prevent the adhesion of S. aureus, L. monocytogenes, V. parahaemolyticus and S. typhimurium to HT-29 cells. Moreover, the inhibitory effect against SARS-CoV-2 and the binding activity to S protein were also positively correlated to molecular weight. These results indicate that natural fucoidan with higher molecular weight are more effective to inhibit these pathogenic bacteria and SARS-CoV-2, providing a better understanding of the relationship between structure and activity of fucoidan against pathogenic microbiota.

Interaction between Bacteroidetes species in the fermentation of Lycium barbarum arabinogalactan.

The present study investigated the utilization of an arabinogalactan from Lycium barbarum (LBP-3) by intestinal Bacteroidetes species. The mixed-culture assay showed 58.4 % LBP-3 was utilized, and Bacteroides caccae and Phocaeicola vulgatus utilized more LBP-3 in single-culture compared to others. During in vitro fermentation of LBP-3, P. vulgatus favored arabinose while B. caccae preferred galactose. Moreover, 9 and 25 oligosaccharides were identified by HPLC-MSn in conditioned media (CM) derived from B. caccae and P. vulgatus, respectively. All of 3 tested Parabacteroides species (P. distasonis, P. goldsteinii, and P. johnsonii) markedly proliferated in CM of B. caccae and P. vulgatus, and proliferations of B. uniformis, B. finegoldii, B. ovatus and B. thetaiotaomicron also increased significantly in CM of B. caccae. The study suggests that the ability of Bacteroidetes species to degrade LBP-3 and sheds light on cooperative interactions of Bacteroides, Phocaeicola, and Parabacteroides species in the presence of LBP-3.

Fucoidan from Scytosiphon lomentaria protects against destruction of intestinal barrier, inflammation and lipid abnormality by modulating the gut microbiota in dietary fibers-deficient mice.

Inadequate dietary fibers intake has been a threat for public health, and its adverse effect and regulatory mechanisms remain unclear. In this study, the protective effect of fucoidan from Scytosiphon lomentaria (SLF) on dietary fibers deficiency (FF)-induced change of physiological functions was analyzed in mice. SLF reduced weight gain and low-density lipoprotein cholesterol, increased high-density lipoprotein cholesterol, but had no effect on food intake and body fat mass in FF-treated mice. Lipidomics analysis showed that SLF modulated lipid metabolism, mainly involving glycerophospholipid and linolenic acid metabolism pathways. In addition, SLF protected against FF-induced colon damages, including the integrity of epithelial cell layer, loss of goblet cells, crypts and glycoproteins, and inflammatory cells infiltration. The underlying mechanisms can be associated with inhibition of oxidative stress, increase of tight junction proteins, and regulation of cytokines profile via nuclear factor kappa B pathway. On the other hand, SLF modulated FF-induced gut microbiota dysbiosis that had close relation with host physiological functions, e.g. increases in Akkermansia, Parabacteroides, Bacteroides and Alistipes. It indicates that SLF can be developed as a prebiotic agent to benefit host health through protecting intestinal barrier and regulating the gut microbiota.