Seaweed Polysaccharides Research Articles

Effects of Seaweed Polysaccharide on the Growth and Physiological Health of Largemouth Bass, Micropterus salmoides

A seven-week trial was designed to evaluate the effects of dietary seaweed polysaccharide (SP) supplementation on the growth performance and physiological health of largemouth bass. The results reveal that the 0.05SP group showed the best growth performance. The mRNA expression levels of tor, 4ebp1, and igf1 genes were remarkably down-regulated in the 0.15SP and 0.2SP groups compared to the control group. The CAT activities were significantly increased in the 0.05SP and 0.1SP groups, and the GSH-Px activity was increased in the 0.15SP group. The expression of the immune response-related gene nfκb was significantly down-regulated in the 0.1SP group, and those of tnfα and il-8 were at the maximum in the control group. Moreover, the expression of il-10 in the 0.15SP and 0.2SP groups was significantly down-regulated. Furthermore, endoplasmic reticulum stress (ERS)-related expression of atf6 was the highest in the control group. Furthermore, the chopα and bax expression levels in the 0.15SP and 0.2SP groups were significantly down-regulated compared with other groups. In addition, the highest expression level of bcl-xl was observed in the 0.15SP group. Finally, the quadratic regression analysis of antioxidant, immune, and ERS core parameters (CAT, nf-κb, and bcl-xl) determined 0.06–0.11% to be the optimal SP supplemental level in largemouth bass diets.

Marine Seaweed Polysaccharides: An Insight into Biological Activities and Biomedical Applications

: Natural products from various sources play a major role in the healthcare sector, mainly in the pharmaceutical, cosmetic, agro and medical divisions. Polysaccharides are one of the important biomacromolecules present in higher plants, animals, fungi and algae, and aid in the growth and development of an organism. They play a vital role in regulating and maintaining cellular homeostasis in all forms of life. They are considered bioactive polymers and possess promising beneficial effects on human health without any harmful side effects. Among different biopolymers, polysaccharides have gained greater attention in the area of natural products and biomedical research due to their unique physio-chemical properties, bioactivities and health-promoting effects. The molecular structure of the polysaccharides is highly complex, depending on their origin and the structural diversity. Carbohydrate polymers differ largely based on their molecular weight, composition, functional derivatives, pattern of glycosidic linkages and degree of polymerization. In recent years, seaweed polysaccharides have been identified in large numbers and are effectively used by the food and biotechnology industries for the production of nutraceutical and pharmaceutical products. Several researches have demonstrated the biological activities of seaweed polysaccharides such as antioxidant, antiviral, hypoglycemic, antidiabetic, antitumor and immunomodulatory. Moreover, there has been a substantial increase in the utilization of natural polymeric biomaterials in the biomedical field. This review summarizes the diverse biological effects of polysaccharides derived from different types of seaweeds as well as their biomedical applications. The information reviewed here provides an insight into the biopotential efficiency of algal-based polysaccharides, further help in the development of novel pharmaceutical and biomedical products.

Development of a Whey Protein Recovery Process Using Sugar Kelp (Saccharina latissima) Extracts.

Whey is the largest waste product of the cheese-making industry and the current methods of extracting the nutrients from it are costly and inefficient. This study assessed the feasibility of using crude polysaccharides to flocculate proteins from liquid whey waste. The flocculants used were a sugar kelp (Saccharina latissima) extract, as well as commercial seaweed polysaccharides, alginate and k-carrageenan, to recover proteins from the liquid whey waste. Physicochemical and functional parameters including protein content, protein recovery efficiency, mineral content, total phenolic content (TPC), antioxidant capacity, color, water- and oil-holding capacity, gelling capacity, foaming activity and stability, and emulsifying activity and stability were tested on the resulting flocculates. The yield of the dried flocculates by use of alginate, the sugar kelp polysaccharide extract (SKPE), and carrageenan were 1.66, 0.98, and 1.22 g/100 g of liquid whey with protein contents of 27.4%, 45.5%, and 37.5%, respectively. The protein recovery efficiency from the whey was 57.5%, 56.2%, and 57.9% using alginate, SKPE, and carrageenan, respectively. The alginate flocculate had the highest oil-holding capacity and foaming abilities while the carrageenan flocculate had the best gelling ability and the highest emulsifying activity and stability. TPC and antioxidant activity were highest in the SKPE flocculate. All three flocculates presented slightly different compositional and functional qualities, which could be used for a variety of products. This study showed that seaweed polysaccharides present a simple and effective way to extract protein from liquid whey waste while creating a functional and high-protein ingredient.

Physicochemical characterization of bioactive polysaccharides from three seaweed and application of functional fruit packaging films

Seaweed polysaccharides show tremendous research and application value because of their significant and unique biological activities. However, reports on seaweed polysaccharides usually focus on in-depth studies of a specific biological activity, which severely limits their further development. Herein, three seaweed polysaccharides were isolated from Undaria pinnatifida (UPPS), Sargassum pallidum (SPPS), and Ulva lactuca (ULPS), respectively. The physicochemical properties, structure, rheological properties, antioxidant activities, antibacterial activities, and anti-glycation activities of UPPS, ULPS, and SPPS were comprehensively studied. It was first demonstrated that SPPS and UPPS had triple prominent biological activities. SPPS exhibited the best biological activities in antioxidation (IC50 in the ABTS test: 0.4616 ± 0.0134 mg/mL), antibacterial effect, and anti-glycation activity (inhibitory rate: 84.74 ± 0.07 %). Additionally, UPPS films (UPPSF) demonstrated superior ultraviolet shielding performance, lower water vapor permeability (1.78 ± 0.01 g/m·s·Pa × 10−11), higher hydrophobicity (water contact angle: 96.91 ± 2.52°), and higher antioxidant activity compared to ULPS films (ULPSF). UPPSF and ULPSF effectively prolonged the shelf life of strawberries to six days, and UPPSF showed better preservation properties. This work provides novel theoretical insights into the use of polysaccharides as medicinal nutraceuticals, bioactive agents, and food packaging films.

Targeted metagenomics – Enrichment for enzymes active on sulfated polysaccharides from seaweeds

Seaweeds (macroalgae) are an attractive resource for diverse microbial- and enzymatic production processes. They are abundant, underutilized, cheap, and rich in carbohydrates, and therefore have the potential to be used as a source of mono- or oligosaccharides, and as substrates for industrial fermentation processes. Many seaweed polysaccharides, including the sulfated polysaccharides ulvan and fucoidan, are however complex and heterogenous in structure, and there are currently few enzymes available to modify them, and understanding of their enzymatic depolymerization remains limited. The present study aimed to identify and characterize robust fucoidanases and ulvan lyases. Metagenomes were obtained from microbial enrichments from an intertidal hot-spring, genes identified that expressed putative fucoidanases and ulvan lyases, and following gene cloning and expression, the respective enzymes were screened for enzymatic activity. Consistent with their origin, the identified protein sequences were considerably divergent from previously characterized enzymes, with a 44 % average maximal sequence identity. In total, the study resulted in the characterization of 10 new fucoidanases (GH107 and GH168 families) and 8 new ulvan lyases (PL24, PL25 and PL40 families). Notably, the new fucoidanases appeared to have functional specificity towards fucoidan containing α-1,3 linked L-fucosyl and several functioned at high temperature. The study contributes a metagenomics-based approach to identify new seaweed polysaccharide degrading enzymes and an increased understanding of the diversity of such enzymes, which may have implications for the realization of biotechnology based valorization of seaweed biomass.

Red Seaweed (Rhodophyta) Phycocolloids: A Road from the Species to the Industry Application.

Seaweed polysaccharides are versatile both in their functions in seaweed physiology and in their practical applications in society. However, their content and quality vary greatly. This review discusses the main factors that influence the yield and quality of polysaccharides, specifically carrageenans and agars (sulfated galactans) found in red algae species (Rhodophyta). In addition, its historical, current, and emerging applications are also discussed. Carrageenan has been influenced mainly by photosynthetically active radiation (PAR) and nitrogen, while its relationship with temperature has not yet been replicated by recent studies. Agar's seasonal trend has also been found to be more ambiguous than stated before, with light, temperature, nutrients, and pH being influencing factors. In this review, it is also shown that, depending on the compound type, seaweed polysaccharides are influenced by very different key factors, which can be crucial in seaweed aquaculture to promote a high yield and quality of polysaccharides. Additionally, factors like the extraction method and storage of polysaccharides also influence the yield and quality of these compounds. This review also highlights the drawbacks and inadequacy inherent from the conventional (or current) extraction technology approaches.

Comparison of Polysaccharide Profiles of Different Seaweeds Based on Ion Chromatography and Ultrahigh‐Performance Liquid Chromatography

ABSTRACTIn traditional Chinese medicine research, seaweeds used for drug and health food development mainly refer to Sargassum pallidum (Turn.) C. Ag. (SP) and Sargassum fusiforme (Harv.) Setch. (SF). In the Chinese Pharmacopoeia, polysaccharides are the main quality control indicators. The total sugar content is determined by the anthrone–sulfuric acid method to evaluate the quality of seaweeds. However, this method cannot reflect the structural characteristics of seaweed polysaccharides and cannot distinguish among different seaweed varieties. Given this, to comprehensively evaluate the quality of different seaweeds, this study conducted a thorough analysis of the primary structure of polysaccharides in 11 batches of SF and 7 batches of SP. The neutral sugar content was determined by the anthrone–sulfuric acid colorimetric method, weight average molecular weight (Mw) by high‐performance size exclusion chromatography coupled with multi‐angle laser light scattering and refractive index detector method, sulfate content by ion chromatography and monosaccharide composition by ultrahigh‐performance liquid chromatography method, while also using professional software for statistical and similarity analysis. The results showed significant differences (p < 0.05) in neutral sugar content and Mw between S. fusiforme polysaccharides and S. pallidum polysaccharides, which can be used to distinguish SF and SP. The monosaccharide composition fingerprint was analyzed using chemometric methods, and it was found that fucose and glucose could serve as differential markers to distinguish SF and SP. This study further deepens the understanding of polysaccharides in seaweeds and more comprehensively evaluates the quality of different seaweeds.

A Comparative Analysis of the Anti-Tumor Activity of Sixteen Polysaccharide Fractions from Three Large Brown Seaweed, Sargassum horneri, Scytosiphon lomentaria, and Undaria pinnatifida.

Searching for natural products with anti-tumor activity is an important aspect of cancer research. Seaweed polysaccharides from brown seaweed have shown promising anti-tumor activity; however, their structure, composition, and biological activity vary considerably, depending on many factors. In this study, 16 polysaccharide fractions were extracted and purified from three large brown seaweed species (Sargassum horneri, Scytosiphon lomentaria, and Undaria pinnatifida). The chemical composition analysis revealed that the polysaccharide fractions have varying molecular weights ranging from 8.889 to 729.67 kDa, and sulfate contents ranging from 0.50% to 10.77%. Additionally, they exhibit different monosaccharide compositions and secondary structures. Subsequently, their anti-tumor activity was compared against five tumor cell lines (A549, B16, HeLa, HepG2, and SH-SY5Y). The results showed that different fractions exhibited distinct anti-tumor properties against tumor cells. Flow cytometry and cytoplasmic fluorescence staining (Hoechst/AO staining) further confirmed that these effective fractions significantly induce tumor cell apoptosis without cytotoxicity. qRT-RCR results demonstrated that the polysaccharide fractions up-regulated the expression of Caspase-3, Caspase-8, Caspase-9, and Bax while down-regulating the expression of Bcl-2 and CDK-2. This study comprehensively compared the anti-tumor activity of polysaccharide fractions from large brown seaweed, providing valuable insights into the potent combinations of brown seaweed polysaccharides as anti-tumor agents.

Chemically modified seaweed polysaccharides: Improved functional and biological properties and prospective in food applications.

Seaweed polysaccharides are natural biomacromolecules with unique physicochemical properties (e.g., good gelling, emulsifying, and film-forming properties) and diverse biological activities (e.g., anticoagulant, antioxidant, immunoregulatory, and antitumor effects). Furthermore, they are nontoxic, biocompatible and biodegradable, and abundant in resources. Therefore, they have been widely utilized in food, cosmetics, and pharmaceutical industries. However, their properties and bioactivities sometimes are not satisfactory for some purposes. Modification of polysaccharides can impart the amphiphilicity and new functions to the biopolymers and change the structure and conformation, thus effectively improving their functional properties and biological activities so as to meet the requirement for targeted applications. This review outlined the modification methods of representative red algae polysaccharides (carrageenan and agar), brown algae polysaccharides (fucoidan, alginate, and laminaran), and green algae polysaccharides (ulvan) that have potential food applications, including etherification, esterification, degradation, sulfation, phosphorylation, selenylation, and so on. The improved functional properties and bioactivities of the modified seaweed polysaccharides and their potential food applications are also summarized.

Seaweed as Basis of Eco-Sustainable Plastic Materials: Focus on Alginate.

Seaweed, a diverse and abundant marine resource, holds promise as a renewable feedstock for bioplastics due to its polysaccharide-rich composition. This review explores different methods for extracting and processing seaweed polysaccharides, focusing on the production of alginate plastic materials. Seaweed emerges as a promising solution, due to its abundance, minimal environmental impact, and diverse industrial applications, such as feed and food, plant and soil nutrition, nutraceutical hydrocolloids, personal care, and bioplastics. Various manufacturing techniques, such as solvent casting, injection moulding, and extrusion, are discussed for producing seaweed-based bioplastics. Alginate, obtained mainly from brown seaweed, is particularly known for its gel-forming properties and presents versatile applications in many sectors (food, pharmaceutical, agriculture). This review further examines the current state of the bioplastics market, highlighting the growing demand for sustainable alternatives to conventional plastics. The integration of seaweed-derived bioplastics into mainstream markets presents opportunities for reducing plastic pollution and promoting sustainability in material production.

Extraction, Purification, Structural Characteristics, and Biological Activities of Seaweed Polysaccharides: A Review

AbstractThis paper presents a thorough review of the extraction, purification, structural characterization, and biological activities of polysaccharides obtained from seaweed. The focus is on the polysaccharide compositions of green algae, brown algae, and red algae, which are systematically compared and analyzed. It has been discovered that while there are similarities in the extraction and purification processes of seaweed polysaccharides, there are also significant differences and unique features in their structural characteristics and biological activities. These differences are not only reflected in the chemical composition of the polysaccharides but are also closely related to their sources and extraction methods. The relationship between the structure and activity of seaweed polysaccharides will aid in comprehending the biological activity mechanism of marine organisms. This review provides a theoretical basis and practical guidance for the development of new types of marine drugs or functional foods.

Exploring potential polysaccharide utilization loci involved in the degradation of typical marine seaweed polysaccharides by Bacteroides thetaiotaomicron.

Research on the mechanism of marine polysaccharide utilization by Bacteroides thetaiotaomicron has drawn substantial attention in recent years. Derived from marine algae, the marine algae polysaccharides could serve as prebiotics to facilitate intestinal microecological balance and alleviate colonic diseases. Bacteroides thetaiotaomicron, considered the most efficient degrader of polysaccharides, relates to its capacity to degrade an extensive spectrum of complex polysaccharides. Polysaccharide utilization loci (PULs), a specialized organization of a collection of genes-encoded enzymes engaged in the breakdown and utilization of polysaccharides, make it possible for Bacteroides thetaiotaomicron to metabolize various polysaccharides. However, there is still a paucity of comprehensive studies on the procedure of polysaccharide degradation by Bacteroides thetaiotaomicron. In the current study, the degradation of four kinds of marine algae polysaccharides, including sodium alginate, fucoidan, laminarin, and Pyropia haitanensis polysaccharides, and the underlying mechanism by Bacteroides thetaiotaomicron G4 were investigated. Pure culture of Bacteroides thetaiotaomicron G4 in a substrate supplemented with these polysaccharides were performed. The change of OD600, total carbohydrate contents, and molecular weight during this fermentation were determined. Genomic sequencing and bioinformatic analysis were further performed to elucidate the mechanisms involved. Specifically, Gene Ontology (GO) annotation, Clusters of Orthologous Groups (COG) annotation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were utilized to identify potential target genes and pathways. Underlying target genes and pathways were recognized by employing bioinformatic analysis. Several PULs were found that are anticipated to participate in the breakdown of these four polysaccharides. These findings may help to understand the interactions between these marine seaweed polysaccharides and gut microorganisms. The elucidation of polysaccharide degradation mechanisms by Bacteroides thetaiotaomicron provides valuable insights into the utilization of marine polysaccharides as prebiotics and their potential impact on gut health. Further studies are warranted to explore the specific roles of individual PULs and their contributions to polysaccharide metabolism in the gut microbiota.

Insights into immunoregulatory effects of bioactive polysaccharides derived from seaweeds through gut microbiota

Seaweeds polysaccharides possess diverse structures and functions, extending beyond culinary uses to potentially offer health benefits. Notable among seaweed polysaccharides are fucoidans, carrageenans, galactans, agars, alginates, and laminarin etc. These bioactive compounds exhibit a range of biological activities, including antioxidant, anti-inflammatory, antiviral, and immunomodulatory effects. Seaweed polysaccharides, characterized by their unique structural complexity, present themselves as promising candidates for immunomodulation. This review provides an overview of the intricate connections between gut microbiota, immune system dynamics, and the prebiotic potential of seaweed polysaccharides. The review highlights the prebiotic effects of seaweed polysaccharides, examining their fermentation in the colon, promotion of beneficial bacteria, and inhibition of pathogens. This section presents the significant discoveries from the review, categorizing them based on the types of seaweeds studied which are brown, red, and green. It highlights the distinct prebiotic effects associated with the polysaccharide. The conclusion summarizes the key insights derived from the dynamic interplay of gut microbiota, seaweed polysaccharides, and their prebiotic effects.

Seaweed Polysaccharides as Potential Biostimulants in Turnip Greens Production

Seaweed polysaccharides can act as substitutes for synthetic compounds present in commercial stimulants and fertilizers used in agriculture to improve crop yields and vigor. In this study, three different polysaccharides (alginate, agar, and carrageenan) were extracted from one brown seaweed, Saccorhiza polyschides, and two red seaweeds, Gracilaria gracilis and Chondrus crispus, respectively, and applied to potted turnip greens (Brassica napus L.), with the intention to analyze their impact on plant growth, development, and metabolism. Turnip greens treated with polysaccharides, especially carrageenan of C. crispus, showed the best results in improving the crop productivity in terms of plant length and weight, number of leaves, nutrient and pigment content, and soil fertility compared with turnip greens from the negative control or those treated with a commercial leaf fertilizer. λ-carrageenan extracted from the tetrasporophyte generation of C. crispus had the highest bioactivity and positive effect on turnip greens among all treatments. λ-carrageenan has been shown to improve plant growth; increase the plant’s biomass (plant leaves: CC(T) (40.80 ± 5.11 g) compared to the positive control (15.91 ± 15.15 g)) and root system; enhance photosynthetic activity; increase the uptake of soil nutrients; and protect plants against abiotic and biotic stresses, stimulating the production of secondary metabolites and managing its defense pathways. Seaweed-extracted polysaccharides have the potential to be used in sustainable agriculture.

Inhibitory effect of a polysaccharide prepared from edible red seaweed Bangia fusco-purpurea on Escherichia coli by regulating its metabolisms

In this study, the antimicrobial activity on Escherichia coli (E. coli) of a polysaccharide (BFP) prepared from Bangia fusco-purpurea with the underlying mechanism was investigated. The results showed that BFP could against the growth of E. coli in a concentration-dependent manner. The inhibitory effect of BFP on E. coli might be through disrupting the morphology, increasing the intracellular reactive oxygen species levels, and decreasing the Ca2+-Mg2+-ATPase activity in E. coli. Furthermore, BFP significantly reduced the biofilm formation in E. coli by down-regulating the critical biofilm-related genes, including flhD, flhC, fliM, csgA, and csgD, especially fliM, and weakened the bacteria's infection and pathogenic potentials. Notably, the metabolomic analysis demonstrated that BFP performed antimicrobial activity mainly by up-regulating the sphingosine and phospholipids metabolites, down-regulating the amino acid metabolites, and the two-component system in E. coli. The findings advance the understanding on the underlying mechanisms of red seaweed polysaccharide BFP against E. coli, and further provide the scientific basis for developing BFP as a natural antimicrobial agent applied in food additives or pharmaceutical ingredients.

Comparison of Chemical Composition and Bioactivities of Polysaccharides of Brown Seaweeds, the Red Sea, Egypt, Hurghada

Sulfated polysaccharides (SPs) from algae have been shown to be effective in a number of biological applications. Therefore, the chemical composition and different biological functions of various SPs were determined for three brown seaweed species from the Egyptian Red Sea: <i>Dictyopteris polypodioides, Polycladia myrica</i>, and <i>Turbinaria decurrens</i>. It has been found that the yield of crude SPs was higher than that of alginate and fucoidan with a range of 43.64% to 61.90%. Fucoidan, which has the maximum carbohydrate content of 56.89%, was found in <i>D. polypodioides.</i> The crude SPs of <i>P. myrica </i>had the greatest sulfate content of 22.44%. All functional groups of the examined samples were confirmed by the Fourier Transform Infrared spectrum (FTIR). Experimentally, three applicable assays were used to quantify the antioxidant activity of the extracted SPs depending on the method used, the type of polysaccharides, and algal species. The anti-diabetic activity of <i>T. decurrens</i>-crude SPs was highly active scoring 85.85% in the α-glucosidase assay. The anti-obesity activity showed the highest value (95.25%) for <i>T. decurrens</i>-fucoidan. Besides, <i>T. decurrens</i>-crude SPs showed the highest anti-arthritic activity (89.89%). In addition, a few positive records of antibacterial activity were detected. Furthermore, the most potent <i>T. decurrens</i>-crude SPs extract was tested for cytotoxicity against human liver cells and found to be safe. The activity of the isolated SPs and their chemical composition were shown to be correlated. Conclusively, the bioactivities recorded herein by the tested SPs pose promising medicinal applications towards developing a new therapeutic intervention.

Preparation of Multifunctional Seaweed Polysaccharides Derivatives Composite Hydrogel to Protect Ultraviolet B-Induced Photoaging In Vitro and In Vivo.

Seaweed polysaccharides can be used for protective skin photoaging which is caused by long-term exposure to ultraviolet B (UVB). In this study, a multifunctional composite hydrogel (FACP5) is prepared using sulfated galactofucan polysaccharides, alginate oligosaccharides as active ingredients, and polyacrylonitrile modified κ-Carrageenan as substrate. The properties of FACP5 show that it has good water retention, spreadability, and adhesion. The antiphotoaging activity is evaluated in vitro and in vivo. In vitro experiments demonstrate that the components of FACP5 exhibit good biocompatibility, antioxidant, and anti-tyrosinase activities, and could reduce the cell death rate induced by UVB. In vivo experiments demonstrate that, compared with the mice skin in model group, the skin water content treated with FACP5 increases by 29.80%; the thicknesses of epidermis and dermis decrease by 53.56% and 43.98%, respectively; the activities of catalase and superoxide dismutase increase by 1.59 and 0.72 times, respectively; the contents of interleukin-6 and tumor necrosis factor-α decrease by 19.21% and 17.85%, respectively; hydroxyproline content increases by 32.42%; the expression level of matrix metalloproteinase-3 downregulates by 42.80%. These results indicate that FACP5 has skin barrier repairing, antioxidant, anti-inflammatory, and inhibiting collagen degradation activies, FACP5 can be used as a skin protection remedy for photoaging.

Seaweed polysaccharides on seed germination of Brassica napus L.

Seaweed polysaccharides, when compared to synthetic commercial fertilizers, have been proven to achieve excellent results in plant growth parameters. When applied to the soil directly or sprayed on the foliage, seaweed poly- and oligosaccharides can improve seed germination and plant vigor, increase the uptake of soil nutrients, and protect plants against several abiotic and biotic stresses, by stimulating a plant to produce secondary metabolites and manage its defense pathways. In this study, three different polysaccharides (alginate, agar and carrageenan) were extracted from one brown seaweed, Saccorhiza polyschides, and two red seaweeds, Gracilaria gracilis and Chondrus crispus, respectively, with aim to analyse their impact on Brassica napus L. seed germination. The polysaccharides' chemical structure, mineral profile and other physicochemical properties were assessed. Carrageenan exhibited the best results in seedling growth and germination percentage when compared to alginate and agar. The carrageenan extracted from the tetrasporophyte, non-fructified thalli and female gametophyte of Chondrus crispus exhibited 94.67, 92 and 98.67 % seed germination, respectively. Carrageenan's bioactivities appear to be related with their sulphation level, plus the pH and the conductivity of its solution. The optimum concentration for germination of each polysaccharides' solution was assigned to propose further experiments in turnip greens.

Effects of Enteromorpha prolifera polysaccharides on growth performance, intestinal barrier function and cecal microbiota in yellow-feathered broilers under heat stress

BackgroundGlobal warming leading to heat stress (HS) is becoming a major challenge for broiler production. This study aimed to explore the protective effects of seaweed (Enteromorpha prolifera) polysaccharides (EPS) on the intestinal barrier function, microbial ecology, and performance of broilers under HS. A total of 144 yellow-feathered broilers (male, 56 days old) with 682.59 ± 7.38 g were randomly assigned to 3 groups: 1) TN (thermal neutral zone, 23.6 ± 1.8 °C), 2) HS (heat stress, 33.2 ± 1.5 °C for 10 h/d), and 3) HSE (HS + 0.1% EPS). Each group contained 6 replicates with 8 broilers per replicate. The study was conducted for 4 weeks; feed intake and body weights were measured at the end of weeks 2 and 4. At the end of the feeding trial, small intestine samples were collected for histomorphology, antioxidant, secretory immunoglobulin A (sIgA) content, apoptosis, gene and protein expression analysis; cecal contents were also collected for microbiota analysis based on 16S rDNA sequencing.ResultsDietary EPS promoted the average daily gain (ADG) of broilers during 3–4 weeks of HS (P < 0.05). At the end of HS on broilers, the activity of total superoxide dismutase (T-SOD), glutathione S-transferase (GST), and the content of sIgA in jejunum were improved by EPS supplementation (P < 0.05). Besides, dietary EPS reduced the epithelial cell apoptosis of jejunum and ileum in heat-stressed broilers (P < 0.05). Addition of EPS in HS group broilers' diet upregulated the relative mRNA expression of Occludin, ZO-1, γ-GCLc and IL-10 of the jejunum (P < 0.05), whereas downregulated the relative mRNA expression of NF-κB p65, TNF-α and IL-1β of the jejunum (P < 0.05). Dietary EPS increased the protein expression of Occludin and ZO-1, whereas it reduced the protein expression of NF-κB p65 and MLCK (P < 0.01) and tended to decrease the protein expression of TNF-α (P = 0.094) in heat-stressed broilers. Furthermore, the proportions of Bacteroides and Oscillospira among the three groups were positively associated with jejunal apoptosis and pro-inflammatory cytokine expression (P < 0.05) and negatively correlated with jejunal Occludin level (P < 0.05). However, the proportions of Lactobacillus, Barnesiella, Subdoligranulum, Megasphaera, Collinsella, and Blautia among the three groups were positively related to ADG (P < 0.05).ConclusionsEPS can be used as a feed additive in yellow-feathered broilers. It effectively improves growth performance and alleviates HS-induced intestinal injury by relieving inflammatory damage and improving the tight junction proteins expression. These beneficial effects may be related to inhibiting NF-κB/MLCK signaling pathway activation and regulation of cecal microbiota.

Polysaccharides from red seaweeds: Effect of extraction methods on physicochemical characteristics and antioxidant activities

Seaweed polysaccharides are reported to possess biological and medicinal properties. Specifically, the antioxidant activity of seaweed extracts is the subject of intensive research due to ever-increasing demands from the food and pharmaceutical industries. The structure and composition of polysaccharides (carrageenan, xylan) extracted from four red seaweed species: Chondrus crispus (CC), Ahnfeltiopsis devoniensis (AD), Sarcodiotheca gaudichaudii (SG) and Palmaria palmata (PP) were compared and correlated with their antioxidant activity. Crude polysaccharide extracts were characterized by NMR (1H and 13C), HPLC-SEC, and FTIR spectroscopy. Total phenolic content (TPC), total sugars, sulfate and protein content were determined using spectrophotometric methods. The antioxidant capacity of each fractionated polysaccharide sample was evaluated by the following methods: DPPH (2,2-diphenyl-1-picrylhydrazyl radical), ABTS (2,2-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid]), superoxide dismutase (SOD), ferric-reducing power in FRAP (Ferric-reducing Antioxidant Power) assays, and the hydroxyl radical (OH) scavenging capacity assay. The highest antioxidant activity was found in extracts from A. devoniensis (ι/κ hybrid carrageenan), while the lowest was in P. palmata (xylans). Moreover, Chondrus crispus extracts did not possess SOD inhibition activity. Polysaccharides evaluated in this study offer high potential for applications in the food, pharmaceutical and biotechnology industries.