Synthesis of chitosan oligosaccharide selenium and its antitumor activity

Background:Polysaccharides have various biological activities;the complexation of polysaccharides with trace element ions can produce synergistic effects,improving the original biological activities of sugars and trace elements.Methods:The preparation process of chitosan oligosaccharide selenium(COSSe)was optimized by the response surface method,followed by a detailed analysis of the resultant compound’s characteristics.The anti-cancer activity of COSSe was studied using the human ovarian cancer cell line SKOV3 as a cell model.Results:The prepared COSSe response surface was well predicted,indicating successful chitosan oligosaccharide binding with selenium.Response surface method analyses identified the optimal synthesis conditions for COSSe:the reaction time of 5.08 h,the reaction temperature of 71.8°C,and mass ratio(Na2SeO3:chitosan oligosaccharide)of 1.02.Under the optimal conditions,the final product,the selenium content,reached 1.302%.The results of cell experiments showed that COSSe significantly inhibited SKOV3 proliferation in a concentration-dependent manner.RNA-seq results showed that chitosan oligosaccharide and COSSe significantly modulated the expression of genes’DNA metabolic processes and cell cycle in SKOV3 cells.Gene enrichment analysis showed the inhibition of the cell cycle,and the results of flow cytometry showed that SKOV3 cells increased in the S phase and decreased in the G2/M phase,with a noted suppression in the protein expression of cyclin-dependent kinase 2(CDK2)and cyclin A1(CCNA1).Conclusion:COSSe has a stronger effect than chitosan oligosaccharide,leading to the arrest of the cell cycle in the S phase.Thus,COSSe may be an effective candidate for the treatment of ovarian cancer.

Alginate oligosaccharide-mediated butyrate-HIF-1α axis improves skin aging in mice

The“gut-skin”axis has been proved and is considered as a novel therapy for the prevention of skin aging.The antioxidant efficacy of oligomannonic acid(MAOS)makes it an intriguing target for use to improve skin aging.The present study further explored whereby MAOS-mediated gut-skin axis balance prevented skin aging in mice.The data indicated the skin aging phenotypes,oxidative stress,skin mitochondrial dysfunction,and intestinal dysbiosis(especially the butyrate and HIF-1a levels decreased)in aging mice.Similarly,fecal microbiota transplantation(FMT)from aging mice rebuild the aging-like phenotypes.Further,we demonstrated MAOS-mediated colonic butyrate-HIF-1a axis homeostasis promoted the entry of butyrate into the skin,upregulated mitophagy level and ultimately improving skin aging via HDAC3/PHD/HIF-1a/mitophagy loop in skin of mice.Overall,our study offered a better insights of the effectiveness of alginate oligosaccharides(AOS),promised to become a personalized targeted therapeutic agents,on gut-skin axis disorder inducing skin aging.

In situ visualization of the cellular uptake and sub-cellular distribution of mussel oligosaccharides

Unlike chemosynthetic drugs designed for specific molecular and disease targets,active small-molecule natural products typically have a wide range of bioactivities and multiple targets,necessitating extensive screening and development.To address this issue,we propose a strategy for the direct in situ microdynamic examination of potential drug candidates to rapidly identify their effects and mechanisms of action.As a proof-of-concept,we investigated the behavior of mussel oligosaccharide(MOS-1)by tracking the subcellular dynamics of fluorescently labeled MOS-1 in cultured cells.We recorded the entire dynamic process of the localization of fluorescein isothiocyanate(FITC)-MOS-1 to the lysosomes and visualized the distribution of the drug within the cell.Remarkably,lysosomes containing FITC-MOS-1 actively recruited lipid droplets,leading to fusion events and increased cellular lipid consumption.These drug behaviors confirmed MOS-1 is a candidate for the treatment of lipid-related diseases.Furthermore,in a high-fat HepG2 cell model and in high-fat diet-fed apolipoprotein E(ApoE)^(-/-)mice,MOS-1 significantly promoted triglyceride degradation,reduced lipid droplet accumulation,lowered serum triglyceride levels,and mitigated liver damage and steatosis.Overall,our work supports the prioritization of in situ visual monitoring of drug location and distribution in subcellular compartments during the drug development phase,as this methodology contributes to the rapid identification of drug indications.Collectively,this methodology is significant for the screening and development of selective small-molecule drugs,and is expected to expedite the identification of candidate molecules with medicinal effects.

Structural elucidation of mulberry leaf oligosaccharide and its selective promotion of gut microbiota to alleviate type 2 diabetes mellitus

Two oligosaccharide fractions(MLO 2-1 and 2-2)were purified from enzymatic hydrolysate of mulberry leaf polysaccharide.The results of simulated digestion showed that MLO 2-2 was a digestible oligosaccharide,which could be degraded by human digestive juice;while MLO 2-1 possessed the non-digestible property in the upper gastrointestinal tract and performed the function by regulating the gut microbiota.Hence,MLO 2-1 was selected for the further analysis.The structure of MLO 2-1 was elucidated as follow:α-T-Glcp-(1→3)-β-Glcp-(1→5)-α-Araf-(1→5)-α-Araf-1→5)-α-Araf-(1→3)-α-(2-OAc)-Glcp-1.The in vitro fecal fermentation results showed that MLO 2-1 could modulate the composition of gut microbiota.Meanwhile,MLO 2-1 was effectively metabolized by fecal bacteria to produce lactate and short chain fatty acids,especially acetate and butyrate.The specific metabolic pathways of MLO 2-1 by gut microbiota were further illuminated.Gut microbiota analysis revealed that MLO 2-1 selectively promoted the growth of Ligilactobacillus murinus,a commensal bacterium presented a reduced level in T2DM mice.Animal experiments indicated that MLO 2-1 and L.murinus exhibited hypoglycemic activities.These results demonstrated that MLO 2-1 might alleviate T2DM by selectively accelerating the proliferation of L.murinus.

Physiological and Transcriptome Analysis Illuminates the Molecular Mechanisms of the Drought Resistance Improved by Alginate Oligosaccharides in Triticum aestivum L.

Alginate oligosaccharides(AOS)enhance drought resistance in wheat(Triticum aestivum L.),but the definite mechanisms remain largely unknown.The physiological and transcriptome responses of wheat seedlings treated with AOS were analyzed under drought stress simulated with polyethylene glycol-6000.The results showed that AOS promoted the growth of wheat seedlings and reduced oxidative damage by improving peroxidase and superoxide dismutase activities under drought stress.A total of 10,064 and 15,208 differentially expressed unigenes(DEGs)obtained from the AOS treatment and control samples at 24 and 72 h after dehydration,respectively,were mainly enriched in the biosynthesis of secondary metabolites(phenylpropanoid biosynthesis,flavonoid biosynthesis),carbohydrate metabolism(starch and sucrose metabolism,carbon fixation in photosynthetic organisms),lipid metabolism(fatty acid elongation,biosynthesis of unsaturated fatty acids,alpha-linolenic acid metabolism,cutin,suberine and wax biosynthesis),and signaling transduction pathways.The up-regulated genes were related to,for example,chlorophyll a-b binding protein,amylosynthease,phosphotransferase,peroxidase,phenylalanine ammonia lyase,flavone synthase,glutathione synthetase.Signaling molecules(including MAPK,plant hormones,H_(2)O_(2) and calcium)and transcription factors(mainly including NAC,MYB,MYB-related,WRKY,bZIP family members)were involved in the AOS-induced wheat drought resistance.The results obtained in this study help underpin the mechanisms of wheat drought resistance improved by AOS,and provides a theoretical basis for the application of AOS as an environmentally sustainable biological method to improve drought resistance in agriculture.

Effects of in ovo delivered xylo-and mannan-oligosaccharides on growth performance,intestinal immunity,cecal short-chain fatty acids,and cecal microbiota of broilers

Background:This study investigated a novel in ovo feeding strategy to determine the prebiotic effects of xylo-and mannan-oligosaccharides(XOS and MOS)differing in the degree of polymerization.A total of 192 fertilized eggs were divided into 6 treatment groups:i)normal saline control(NSC),ii)xylotriose(XOS3),iii)xylotetraose(XOS4),iv)mannotriose(MOS3),v)mannotetraose(MOS4),and vi)no injection control(NIC),each containing 4 replicate trays with 8 eggs per replicate.On d 17 of incubation,3 mg of oligosaccharides(except for controls)dissolved in 0.5 mL of 0.85%normal saline were injected into the amnion of Cobb 500 broilers eggs.After hatch,the chicks were raised for 28 d under standard husbandry practices and were fed a commercial broilers diet ad libitum,and samples were collected periodically.Results:The hatchability,growth performance,and relative weights of breast,drumstick,liver,and proventriculus were not different among the treatments(P>0.05).The XOS3 injection increased the total short-chain fatty acid production at d 28 compared with both control groups(P<0.05).The villus height to crypt depth ratio was significantly higher in the XOS4 group than both controls on the hatch day(P<0.01)but were not different among any treatments on d 7 and 28(P>0.05).On the hatch day,the expression level of the CD3 gene(a T cell marker)was increased by XOS3,while the IL-10 gene(a marker of anti-inflammatory cytokine)was reduced by MOS4(P<0.05)compared with both controls.Compared with both controls,XOS3 exhibited a trend of reduction for IL-10(P=0.074).No cytokines or lymphocyte markers were affected by the treatments on d 7(P>0.05),except XOS4 increased IL-4 compared with NSC(P<0.05).The broilers in the MOS4 group had higher operational taxonomic units(OTUs)and had more differentially abundant taxa,including order Lactobacillales and family Leuconostocaceae(P<0.05)than both controls on d 28.The predictive functional profiling indicated that the linoleic acid metabolism pathway was enriched in the cecal microbiota of the XOS3 group compared with both controls(P<0.05).Conclusion:The effects of these XOS and MOS on ileal mucosa and immunity are transient,but the effects on fermentation and cecal microbiota are prolonged,and further research is warranted to determine their use as a gut health promoter in poultry.

Elicitation on Artemisinin Biosynthesis in Artemisia annua Hairy Roots by the Oligosaccharide Extract from the Endophytic Colletotrichum sp. B501

The oligosaccharide elicitor from the mycelial wall of an endophytic Colletotrichum sp. B501 promoted the production of artemisinin in Artemisia annua L. hairy root culture. When hairy roots of 22-day-old cultures (later growth phase) were exposed to the elicitor (20 mg/L) for 4 d, the maximum content of artemisinin reached 1.15 mg/g, a 64.29% increment over the control. The electron X-ray microanalysis disclosed the rapid accumulation of Ca 2+ in the elicited cortical cells of hairy root. The electronic microscope observation revealed the high electron density area in vacuole of elicited cells. During the first day of elicitation the peroxidase activity of hairy roots was improved sharply. Some cellular morphological changes including cell shrinkage, condensation of cytoplasm and nuclear fragmentation, coincident with the appearance of DNA ladders, were observed after the third day of elicitation. It was suggested that the oligosaccharide elicitor triggered the programmed cell death, which may provide the substance or chemical signal for artemisinin biosynthesis.

Cell Apoptosis Induced by Oligosaccharide in Suspension Cultures of Taxus chinensis

Taxol production of Taxus chinensis (Pilger) Rehd. var. mairei (Lemee et Lévl.) Cheng et L. K. Fu induced by oligosaccharide from Fusarium oxysporum f. vasinfectum (Atkinson) Snyder et Hansen was studied in suspension cultures, and it was found that oligosaccharide triggered cell apoptosis. Under transmission electron microscope the following morphological changes were observed: cell shrinkage, condensation of cytoplasm, nuclear fragmentation, and the increase of high electron density bodies in vacuole in great quantity. In oligosaccharide_treated cells, agarose gel electrophoresis revealed that DNA was digested into oligonucleosomal fragments that were times of 200 bp appearing as DNA ladders. Control cells were in normal physiological state, they were intact, abundant in organelle and with integral nucleus DNA, and the rate of taxol biosynthesis in these cells was very low. After the oligosaccharide to the culture system, the defense system of cells was elicited and the secondary metabolism was strengthened, i.e. phenolics were accumulated in the medium, the activity of polyphenol oxidase (PPO) was increased quickly and secondary wall of cells was thickened. The activity of L _phenylalanine ammonia lyase (PAL), the critical enzyme of the phenylpropanoid pathway, was increased promptly 1 h after elicitation. The rate of taxol production was improved sharply and the maximal taxol concentration at 72 h was six times that of control. Appearance of cell apoptosis was accompanied with the highest concentration of taxol in suspension cultures.

Induced Disease Resistance of Antarctic Bacteria B-3 Extracellular Oligosaccharide on Cucumber

[Objective] The induced disease resistance of Antarctic bacteria B-3 extracellular oligosaccharide on cucumber was studied.[Method] Taking the cucumber seedlings as experimental materials,the molecular weight,monosaccharide composition of Antarctic bacteria B-3 extracellular oligosaccharide were studied,its induced effect on the defense enzyme in cucumber leaves and the induced resistance against powdery mildew were also investigated.[Result] Through gel permeation chromatography,the molecular weight of B-3 oligosaccharides was determined to be 2 112 Da;B-3 oligosaccharides was composed by two monosaccharides including of mannose and glucose.The activities of chinitase,β-1,3-glucanse,phenylanine,ammonialyse（PAL）,superoxide dismutase（SOD）,and peroxidase（POD）in cucumber seedlings all increased compared with control when 0.3%,0.5% and 0.8% B-3 extracellular oligosaccharide were sprayed on the seedlings of cucumber for different times,respectively,which had the similar induction effect with 0.5% chitosan;at the same time,0.5% oligosaccharides could significantly reduce the disease index of cucumber powdery mildew,the control effect reached 24.49%.[Conclusion] B-3 oligosaccharides is expected to be developed as a new type of resistance elicitor.

Promotive Effects of Alginate-Derived Oligosaccharides on the Inducing Drought Resistance of Tomato

In order to determine the role of alginate-derived oligosaccharides (ADO) in drought stress resistance of tomato (Ly-copersicon esculentum Miller) seedlings, the leaves were exposed to different concentrations of ADO (0.05%, 0.10%, 0.20%, 0.30% and 0.50%) after drought stress was simulated by exposing the roots to 0.6 molL-1 PEG-6000 solution for 6 h. Changes in biomass, electrolyte leakage and malondialdehyde (MDA), free proline, total soluble sugars (TSS) and abscisic acid (ABA), the enzyme activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and phenylalanine ammonia-lyase (PAL) were measured to investigate the effects of ADO treatment. The results showed that the treatment with an ADO concentration of 0.20% exhibited the highest performance of drought stress resistance in the tomato seedlings by decreasing the electrolyte leakage and the concentration of MDA, increasing the contents of free proline, TSS and ABA, and increasing the activities of CAT, SOD, POD and PAL after treatment with ADO. It is suggested that changes in electrolyte leakage, MDA, osmotic solutes, ABA, anti-oxidative enzyme and PAL activities were responsible for the increased drought stress resistance in tomato seedlings. To our best knowledge, this is the first report of the effect of ADO treatment on enhancing the drought stress resistance of tomato seedlings.

Alginate oligosaccharide-induced intestinal morphology, barrier function and epithelium apoptosis modifications have beneficial effects on the growth performance of weaned pigs

Background: Alginate oligosaccharide(AOS), produced from alginate by alginate lyase-mediated depolymerisation, is a potential substitute for antibiotics and possesses growth-enhancing effects. Nevertheless, the mechanisms by which AOS regulates porcine growth remain to be elucidated. Therefore, we investigated the AOS-mediated changes in the growth performance of weaned pigs by determining the intestinal morphology, barrier function,as well as epithelium apoptosis.Methods: Twenty-four weaned pigs were distributed into two groups(n = 12) and received either a basal diet(control group) or the same diet supplemented with 100 mg/kg AOS. On d 15, D-xylose(0.1 g/kg body weight)was orally administrated to eight randomly selected pigs per treatment, and their serum and intestinal mucosa samples were collected 1 h later.Results: Our results showed that inclusion of AOS in the diet for 2 wk increased(P < 0.05) the average daily body weight gain in weaned pigs. Notably, AOS supplementation ameliorated the intestinal morphology and barrier function, as suggested by the enhanced(P < 0.05) intestinal villus height, secretory immunoglobulin A content and goblet cell counts. Compared to the control group, AOS ingestion both decreased(P < 0.05) the total apoptotic percentage and increased(P < 0.05) the proportion of S phase in the intestinal epithelial cells. Furthermore, AOS not only up-regulated(P < 0.05) the B-cell lymphoma-2(BCL2) transcriptional level but also down-regulated(P < 0.05) the B-cell lymphoma-2-associated X protein(BAX), cysteinyl aspartate-specific proteinase-3(caspase-3) and caspase-9 transcriptional levels in the small intestine.Conclusions: In summary, this study provides evidence that supplemental AOS beneficially affects the growth performance of weaned pigs, which may result from the improved intestinal morphology and barrier function,as well as the inhibited enterocyte death, through reducing apoptosis via mitochondria-dependent apoptosis.

Alginate oligosaccharides preparation, biological activities and their application in livestock and poultry

Alginate oligosaccharides(AOS), belonging to the class of functional marine oligosaccharides, are low-molecular polymers linked by β-1,4-mannuronic acid(M) and α-1,4-guluronic acid(G), which could be classically obtained by enzymatic hydrolysis of alginate. With low viscosity and good water solubility, as well as anti-oxidant, immune regulation, anti-bacterial and antiinflammatory activities, AOS have been widely used in medical science and functional food, green agriculture and other fields. As new bio-feed additives, AOS have broad potential applications in animal husbandry. In this review, the sources of alginate, chemical structure and preparation methods of AOS, and their biological activities and application in livestock and poultry are summarized. We expect this review could contribute to lay a foundation of application and further research for AOS in livestock and poultry.

Alginate oligosaccharide improves resistance to postharvest decay and quality in kiwifruit(Actinidia deliciosa cv. Bruno)

Kiwifruit is an extremely perishable fruit;postharvest disease and senescence during storage can reduce the fruit quality,resulting in economic loss.Considerable research effort has focused on identifying safe and cost-effective ways to preserve fresh kiwifruit.To this end,the present study investigated the effects of alginate oligosaccharide(AOS)soaking treatment on postharvest quality and disease in the‘Bruno’variety of kiwifruit.The involved physiological mechanisms were further explored.The results showed that AOS did not inhibit the growth of Botrytis cinerea in vitro,the causal agent of gray mold in kiwifruit,but reduced the incidence of gray mold and diameter of lesions of kiwifruit during storage.Kiwifruit treated with 50 mg·L-1 AOS showed a higher degree of firmness and lower soluble solid content than control fruit treated with distilled water.Moreover,AOS treatment inhibited the activity of polygalacturonase and pectinesterase,while enhancing the activity of polyphenoloxidase,l-phenylalanine ammonia lyase andβ-1,3-glucanase related to pathogen defense,and also improved total antioxidant capacity determined by the DPPH,FRAP,and ABTS methods in kiwifruit.These results indicate that 50 mg·L-1 AOS can confer disease resistance in kiwifruit during storage.

Gut Bacterial and Lactobacilli Communities of Weaning Piglets in Response to Mannan Oligosaccharide and Sugar Beet Pulp In vitro Fermentation

Microbiota in the gastrointestinal tract （GIT） of piglets during weaning transition can experience a sharp change which could result in growth reduction and diarrhea of weaned piglets. Dietary manipulations can play an important role in attenuating such changes caused by weaning stress. Therefore, ileal and colonic contents of weaned piglets were used as inocula, mannan oligosaccharide （MOS） or sugar beet pulp （SBP） was supplied as single energy sources to investigate effects of MOS or SBP on the shifts of gastro-intestinal microflora and lactobacilli populations. The universal bacteria- and lactobacilli-specific PCR/denaturing gradient gel electrophoresis （DGGE）, cloning and sequencing techniques were used. DGGE profiles of the universal bacteria showed that great changes were found in the position, numbers and intensity of dominant bands after fermentation. The similarity of bacterial community between ileum and colon was increased to 85-97% by MOS or SBP treatment after fermentation from the similarity with 20% before fermentation. MOS treatment significantly increased the bacterial diversity and band number in both ileal and colonic fermentation （P〈0.05）. SBP treatment significantly increased the bacterial diversity and band number in colon （P〈0.05）. It implies that some species were enriched by the addition of MOS or SBP to increase the similarity and diversity of bacterial community in weaned piglets. Five specific bands appearing in MOS or SBP treatment group after fermentation were cloned and sequenced, the changes of species related to Prevotella and Ruminococcus were observed. Two bands related to uncultured bacterium with 98% similarity were detected by MOS or SBP treatment. However, there were no effects on the similarity, diversity index and lactobacilli species revealed by MOS or SBP treatment. These results imply that MOS or SBP could have beneficial effects on the weaning piglets by stablizing microbiota in the GIT microflora.

Effect of Specific Structure of Lotus Seed Oligosaccharides on the Production of Short-chain Fatty Acids by Bifidobacterium adolescentis

In order to study the structure of lotus （Nelumbo nucifera Gaertn） seed oligosaccharides and their effect on the proliferation ofBifidobacterium adolescentis, we extracted the oligosaccharides from seeds collected from Jianning County, China. We preliminarily characterized the groups, molecular weights, molecular formulae, component monosaccharides and glycosidic bonds using mass spectrometry （MS） and nuclear magnetic resonance （NMR） after isolation and purification. The lotus seed oligosaccharides contained glycosidic bonds Manp-（1→）, Galp-（1→）, α（1→6）-Glup and α（1→6）-Manp; and mannose was the chief component monosaccharide. NMR analyses showed that ~t-glycosidic bonds and pyranoid rings were predominant in the oligosaccharides. The MS analyses showed that lotus seed oligosaccharides consisted of three oligosaccharides of different polymerization degree, with relative molecular weights of 342, 504 and 666 Da, and corresponding molecular formulae C12H22O11, C18H32O16 and C24H42O21. Research on the effect of lotus seed oligosaccharides on the proliferation orB. adolescentis showed that they effectively promoted the production of acetic, propionic and butyric acids by B. adolescentis through fermentation, and their effect was stronger than that of fructo-, xylo- and isomalto-oligosaccharides. Lotus seed oligosaccharides have potential as a new functional probiotic and lotus seeds should be further explored and utilized as a source of oligosaccharides.

The Antioxidant Effects of Complexes of Tilapia Fish Skin Collagen and Different Marine Oligosaccharides

An excess of reactive oxygen species（ROS）leads to a variety of chronic health problems.As potent antioxidants,marine bioactive extracts containing oligosaccharides and peptides have been extensively studied.Recently,there is a growing interest in protein-polysaccharide complexes because of their potential uses in pharmaceutical and food industries.However,only few studies are available on the antioxidant activities of such complexes,in terms of their ROS scavenging capability.In this study,we combined and superoxide radicals,and to evaluate the influences on the activities of superoxide dismutase（SOD）,glutathione peroxidase（GSH-Px）and the level of malondialdehyde（MDA）in UV-induced photoaging models.The results indicated that the antioxidant activities of all the complexes were stronger than those of their individual components.Among the 11 complexes tested,two complexes,namely MA1000＋CP and κ-ca3000＋CP,turned out to be highly effective antioxidants.Although the detailed mechanisms of this improved scavenging ability are not fully understood,this work provides insights into the design of highly efficient peptide-oligosaccharide complexes for potential applications in pharmaceutical,cosmetics and food industries.

Chitosan Oligosaccharide-Ca Complex Accelerates the Depuration of Cadmium from Chlamys ferrari

This study investigated the effect of a chitosan oligosaccharide-Ca complex (COS-Ca) on the depuration of cadmium (Cd) from Chlamys ferrari. After exposure to 0.5 mg L-1 CdCl2 for 3 or 7 d, the scallops were treated by COS-Ca prior to determina-tion of Cd, calcium (Ca) and zinc (Zn) contents, Cd distribution in organs, malondialdehyde (MDA) content and antioxidant variables. Results showed that COS-Ca reduced Cd content in the viscera of the scallops, with highest Cd depuration rate (47%) observed on day 3. The COS-Ca concentration substantially affected Cd depuration, and the exposure to 8.75 mg L-1 COS-Ca led to significantly higher Cd depuration rate compared with those of lower COS-Ca concentrations (1.75, 3.5, 5.25, and 7.00 mg L-1). Distribution analysis of Cd in scallop organs indicated that COS-Ca significantly reduced Cd content in the kidney throughout the 5-d experiment, as well as in the gill during the early stage of Cd depuration. In addition, COS-Ca treatment decreased glutathione peroxidase (GSH-Px) activity and MDA content while increasing superoxide dismutase (SOD) and catalase (CAT) activities on different days. Our work suggested COS-Ca complex treatment as an effective method for acceleration of Cd depuration from Cd-contaminated bivalves.

Therapeutic potential and mechanism of functional oligosaccharides in inflammatory bowel disease: a review

Inflammatory bowel disease(IBD)is characterized by recurrent attacks and long courses,and the number of patients has expanded rapidly year by year.Additionally,current conventional strategies exist serious adverse effects.In this case,it is an urgent issue to find out an effective and safe treatment.Functional oligosaccharides possess safe and excellent physiological activities,and have attracted enormous attention due to their great therapeutic potential for IBD.This review emphasizes the attenuating effects of distinct functional oligosaccharides on IBD and their structure,and summarizes the main mechanisms from the aspects of regulating intestinal fl ora structure,repairing intestinal barrier,modulating immune function and mediating related signaling pathways in order to reveal the relationship between functional oligosaccharides,immune regulation,intestinal epithelial cells,gut fl ora and IBD treatment.Oligosaccharides possess excellent protective effects on IBD,and can be considered as safe and functional ingredients in the health food and pharmaceutical industry.

Laminarin and Laminarin Oligosaccharides Originating from Brown Algae:Preparation,Biological Activities,and Potential Applications

Brown algae is one of the three major types of marine algae and includes approximately 2000 species.It is widely dis-tributed in various seas around the world.Brown algae contain a plethora of active substances,such as polysaccharides,polyphe-nols,omega-3 fatty acids,and carotenoids.Laminarin,a type of storage carbohydrate found abundantly in brown algae,is mainly formed by glucose monomers linked byβ-1,3-glucosidic bonds and partialβ-1,6-glucosidic bonds.Laminarin and laminarin oligo-saccharides,which contain 2-10 saccharide units,have extensive biological activities,such as antitumor,antioxidant,anti-inflam-matory,and prebiotic properties.Moreover,both laminarin and laminarin oligosaccharides can be considered as ideal substrates for bioethanol production because they are composed of abundant glucose residues.Therefore,brown algae-derived laminarin and lami-narin oligosaccharides have various potential applications in the food,medicine,cosmetics,and bioenergy fields.This paper reviews the preparation methods of laminarin and laminarin oligosaccharides,as well as their biological activities and potential applications.

Enzymatically prepared alginate oligosaccharides improve broiler chicken growth performance by modulating the gut microbiota and growth hormone signals

Background Alginate oligosaccharide(AOS)holds great potential as a novel feed supplement in farm animals.However,the effects of AOS on chicken health and the underlying mechanisms are not fully understood.This study aimed to optimize the enzymatic preparation of AOS by using bacterial alginate lyases expressed in yeast,investigate the effects of the prepared AOS on the growth performance and gut health of broiler chickens,and reveal the underlying mechanisms.Results Five alginate lyases from bacteria were cloned into Pichia pastoris GS115 and the alginate lyase PDE9 was expressed at relatively high yield,activity and stability in P.pastoris.Animal trials were carried out using 3201-day-old male Arbor Acres broilers(four groups;8 replicates/group×10 chicks/replicate)receiving either a basal diet or the same diet supplemented with 100,200 and 400 mg/kg PDE9-prepared AOS for 42 d.The results showed that dietary supplementation of 200 mg/kg AOS displayed the highest activity in promoting the birds’ADG and ADFI(P<0.05).AOS ameliorated the intestinal morphology,absorption function and barrier function,as indicated by the enhanced(P<0.05)intestinal villus height,maltase activity,and the expression of PEPT,SGLT1,ZNT1,and occludin.AOS also increased serum insulin-like growth factor-1,ghrelin(P<0.05),and growth hormone(P<0.1).Moreover,the concentrations of acetate,isobutyrate,isovalerate,valerate,and total SCFAs in cecum of birds fed AOS were significantly higher than the control birds(P<0.05).Metagenomic analysis indicated that AOS modulated the chicken gut microbiota structure,function,and microbial interactions and promoted the growth of SCFAs-producing bacteria,for example,Dorea sp.002160985;SCFAs,especially acetate,were found positively correlated with the chicken growth performance and growth-related hormone signals(P<0.05).We further verified that AOS can be utilized by Dorea sp.to grow and to produce acetate in vitro.Conclusions We demonstrated that the enzymatically produced AOS effectively promoted broiler chicken growth performance by modulating the chicken gut microbiota structure and function.For the first time,we established the connections among AOS,chicken gut microbiota/SCFAs,growth hormone signals and chicken growth performance.