Digestion Of Polysaccharides Research Articles

On the Origins of Symbiotic Fungi in Carmine Cochineals and Their Function in the Digestion of Plant Polysaccharides.

The cochineal insect Dactylopius coccus Costa (Hemiptera) has cultural and economic value because it produces carminic acid that is used commercially. In this study, distinct fungi were cultured from dissected tissue and identified as Penicillium, Coniochaeta, Arthrinium, Cladosporium, Microascus, Aspergillus, and Periconia. Fungi were microscopically observed inside cochineals in the gut, fat body, and ovaries. Since cochineals spend their lives attached to cactus leaves and use the sap as feed, they can obtain fungi from cacti plants. Indeed, we obtained Penicillium, Aspergillus, and Cladosporium fungi from cacti that were identical to those inside cochineals, supporting their plant origin. Fungi could be responsible for the degrading activities in the insect guts, since cellulase, pectinase, and amylase enzymatic activities in insect guts decreased in fungicide-treated cochineals. Our findings set the basis for the further study of the interactions between insects, fungi, and their host plants.

In vitro digestion and fermentation of polysaccharides from nine common Polygonatum spp. and their impact on human gut microbiota

This study aimed to investigate the dynamic changes in the physicochemical properties of polysaccharides from nine common Polygonatum spp. during in vitro simulated saliva-gastrointestinal digestion, in vitro fermentation, and their subsequent effects on human gut microbiota. Results revealed that the total sugar contents of Polygonatum spp. polysaccharides almost had little changes during the vitro digestion, and the molecular weight presented a downward trend. The in vitro digestion process produced almost no free monosaccharide, with small variations on FT-IR spectroscopy analysis. However, during the in vitro fermentation process, the polysaccharides generated remarkable changes, the total sugar showed a downward trend, and the molecular weight was degraded. There were significant changes in the monosaccharide composition, and possibly the sugar occurred isomerism. Regarding the concentrations of short-chain fatty acids, both acetic acid and propionic acid were found to be significantly elevated in the treatment group compared to the control group, and the pH value dramatically decreased. Simultaneously, Polygonatum spp. polysaccharides could remarkably modulate the richness of microbial communities and improved their diversity, especially Narrowly Defined Clostridium, and Bacteroidetes. In general, this study can be helpful to better understand the potential digestion and fermentation mechanism of the genus Polygonatum polysaccharides.

The predicted secreted proteome of activated sludge microorganisms indicates distinct nutrient niches.

In wastewater treatment plants (WWTPs), complex microbial communities process diverse chemical compounds from sewage. Secreted proteins are critical because many are the first to interact with or degrade external (macro)molecules. To better understand microbial functions in WWTPs, we predicted secreted proteomes of WWTP microbiota from more than 1,000 high-quality metagenome-assembled genomes (MAGs) from 23 Danish WWTPs with biological nutrient removal. Focus was placed on examining secreted catabolic exoenzymes that target major classes of macromolecules. We demonstrate that Bacteroidota has a high potential to digest complex polysaccharides, but also proteins and nucleic acids. Poorly understood activated sludge members of Acidobacteriota and Gemmatimonadota also have high capacities for extracellular polysaccharide digestion. Secreted nucleases are encoded by 61% of MAGs indicating an importance for extracellular DNA and/or RNA digestion in WWTPs. Secreted lipases were the least common macromolecule-targeting enzymes predicted, encoded mainly by Gammaproteobacteria and Myxococcota. In contrast, diverse taxa encode extracellular peptidases, indicating that proteins are widely used nutrients. Diverse secreted multi-heme cytochromes suggest capabilities for extracellular electron transfer by various taxa, including some Bacteroidota that encode undescribed cytochromes with >100 heme-binding motifs. Myxococcota have exceptionally large secreted protein complements, probably related to predatory lifestyles and/or complex cell cycles. Many Gammaproteobacteria MAGs (mostly former Betaproteobacteria) encode few or no secreted hydrolases, but many periplasmic substrate-binding proteins and ABC- and TRAP-transporters, suggesting they are mostly sustained by small molecules. Together, this study provides a comprehensive overview of how WWTPs microorganisms interact with the environment, providing new insights into their functioning and niche partitioning.IMPORTANCEWastewater treatment plants (WWTPs) are critical biotechnological systems that clean wastewater, allowing the water to reenter the environment and limit eutrophication and pollution. They are also increasingly important for the recovery of resources. They function primarily by the activity of microorganisms, which act as a "living sponge," taking up and transforming nutrients, organic material, and pollutants. Despite much research, many microorganisms in WWTPs are uncultivated and poorly characterized, limiting our understanding of their functioning. Here, we analyzed a large collection of high-quality metagenome-assembled genomes from WWTPs for encoded secreted enzymes and proteins, with special emphasis on those used to degrade organic material. This analysis showed highly distinct secreted proteome profiles among different major phylogenetic groups of microorganisms, thereby providing new insights into how different groups function and co-exist in activated sludge. This knowledge will contribute to a better understanding of how to efficiently manage and exploit WWTP microbiomes.

Structural characterization and Bacteroides proliferation promotion activity of a novel homogeneous arabinoglucuronoxylan from Commelina communis L.

Commelina communis L., a functional food and herbal plant in Asia, has been used against obesity, diabetes, and infections for centuries. A growing body of studies has demonstrated that indigestible polysaccharides are significant in obesity management. However, the structures and bioactivities of homogeneous polysaccharides from C. communis remain unclear. This study presented the structural characterization, simulated digestion, and human gut Bacteroides proliferation promotion activity of a novel homogeneous polysaccharide (CCB-3) from C. communis. The results showed that CCB-3 was an arabinoglucuronoxylan, primarily composed of arabinose, galactose, xylose, glucuronic acid (GlcA), and 4-O-methyl GlcA with a molecular weight (Mw) of 58.8 kDa. Following a 6-hour exposure to simulated gastrointestinal fluid, the Mw of CCB-3 remained unchanged, revealing that CCB-3 was an indigestible polysaccharide. Notably, CCB-3 could promote the proliferation of B. thetaiotaomicron, B. ovatus, and B. cellulosilyticus and produce short-chain fatty acids (SCFAs) and 1,2-propanediol. These findings might shed light on the discovery of polysaccharide-based leading compounds from C. communis against obesity.

In vitro simulated digestion of different heat treatments sweet potato polysaccharides and effects on human intestinal flora

The aim of this study was to investigate the changes of untreated and steamed (100 °C, 20 min), fried (150 °C, 10 min), and baked (200 °C, 30 min) sweet potato polysaccharides during in vitro digestion and their effects on the intestinal flora. The results showed that the reducing sugar content of all four sweet potato polysaccharides increased significantly during digestion. During in vitro fecal fermentation, the content of reducing sugars and total carbohydrates decreased significantly. It indicated that all four polysaccharides showed degradation of polysaccharides during fermentation. Compared to the blank group, the total SCFAs content of the four polysaccharide sample groups was significantly increased. It was worth noting that sweet potato polysaccharides increased the percentage of Bacteroidetes and decreased the percentage of Proteobacteria in the intestinal flora. The findings provide evidence that sweet potato polysaccharides regulate intestinal flora and maintain intestinal health through interactions with intestinal flora.

Characterization and in vitro digestion of alkali-extracted polysaccharides from Grifola frondosa and its impacts on human gut microbiota

Grifola frondosa is a highly valued, edible and biologically active fungus in which the polysaccharide component plays a major role. To investigate the fundamental structure, in vitro digestion and fermentation characteristics of Grifola frondosa polysaccharides (GFP), GFP from the waste residue of Grifola frondosa after water extraction was re-extracted by alkaline solution. The carbohydrate and β-glucan contents of GFP were 91.61% and 60.57%, respectively, and were mainly composed of glucose. GFP can form triple supercoils and combine with Congo red, and the surface of GFP was smooth and dense, and the particles were in the shape of long column, sheet and ellipse. Analysis of carbohydrate, reducing sugars, and further chromatogram data also showed that GFP was not degraded by the simulated digestion process of the mouth, stomach and small intestine. Fecal fermentation of GFP significantly increased the abundance of Bacteroidota, and decreased Proteobacterias in both normal weight and obese subjects in vitro. The short-chain fatty acid (SCFA)-producing bacteria, Faecalibacterium, Erysipelotrichaceae_UCG_003, Lactococcus were increased, and Dorea and Escherichia-Shigella were reduced after GFP treatment. Thus, the molecular of GFP was utilized and degraded by the gut microbiota and metabolized into SCFAs. This decreased pH, H2S, and NH3, as well as increased CO2 in the fermentation broth. In conclusion, GFP can modulate the composition of the gut microbiota and is a potentially functional product.

Modifying lignin composition and xylan O-acetylation induces changes in cell wall composition, extractability, and digestibility

BackgroundLignin and xylan are important determinants of cell wall structure and lignocellulosic biomass digestibility. Genetic manipulations that individually modify either lignin or xylan structure improve polysaccharide digestibility. However, the effects of their simultaneous modifications have not been explored in a similar context. Here, both individual and combinatorial modification in xylan and lignin was studied by analysing the effect on plant cell wall properties, biotic stress responses and integrity sensing.ResultsArabidopsis plant co-harbouring mutation in FERULATE 5-HYDROXYLASE (F5H) and overexpressing Aspergillus niger acetyl xylan esterase (35S:AnAXE1) were generated and displayed normal growth attributes with intact xylem architecture. This fah1-2/35S:AnAXE1 cross was named as hyper G lignin and hypoacetylated (HrGHypAc) line. The HrGHypAc plants showed increased crystalline cellulose content with enhanced digestibility after chemical and enzymatic pre-treatment. Moreover, both parents and HrGHypAc without and after pre-treating with glucuronyl esterase and alpha glucuronidase exhibited an increase in xylose release after xylanase digestion as compared to wild type. The de-pectinated fraction in HrGHypAc displayed elevated levels of xylan and cellulose. Furthermore, the transcriptomic analysis revealed differential expression in cell wall biosynthetic, transcription factors and wall-associated kinases genes implying the role of lignin and xylan modification on cellular regulatory processes.ConclusionsSimultaneous modification in xylan and lignin enhances cellulose content with improved saccharification efficiency. These modifications loosen cell wall complexity and hence resulted in enhanced xylose and xylobiose release with or without pretreatment after xylanase digestion in both parent and HrGHypAc. This study also revealed that the disruption of xylan and lignin structure is possible without compromising either growth and development or defense responses against Pseudomonas syringae infection.

Pichia pastoris Mediated Digestion of Water-Soluble Polysaccharides from Cress Seed Mucilage Produces Potent Antidiabetic Oligosaccharides.

Diabetes mellitus is a heterogeneous metabolic disorder that poses significant health and economic challenges across the globe. Polysaccharides, found abundantly in edible plants, hold promise for managing diabetes by reducing blood glucose levels (BGL) and insulin resistance. However, most of these polysaccharides cannot be digested or absorbed directly by the human body. Here we report the production of antidiabetic oligosaccharides from cress seed mucilage polysaccharides using yeast fermentation. The water-soluble polysaccharides extracted from cress seed mucilage were precipitated using 75% ethanol and fermented with Pichia pastoris for different time intervals. The digested saccharides were fractionated through gel permeation chromatography using a Bio Gel P-10 column. Structural analysis of the oligosaccharide fractions revealed the presence of galacturonic acid, rhamnose, glucuronic acid, glucose and arabinose. Oligosaccharide fractions exhibited the potential to inhibit α-amylase and α-glucosidase enzymes in a dose-dependent manner in vitro. The fraction DF73 exhibited strong inhibitory activity against α-amylase with IC50 values of 38.2 ± 1.12 µg/mL, compared to the positive control, acarbose, having an IC50 value of 29.18 ± 1.76 µg/mL. Similarly, DF72 and DF73 showed the highest inhibition of α-glucosidase, with IC50 values of 9.26 ± 2.68 and 50.47 ± 5.18 µg/mL, respectively. In in vivo assays in streptozotocin (STZ)-induced diabetic mice, these oligosaccharides significantly reduced BGL and improved lipid profiles compared to the reference drug metformin. Histopathological observations of mouse livers indicated the cytoprotective effects of these sugars. Taken together, our results suggest that oligosaccharides produced through microbial digestion of polysaccharides extracted from cress seed mucilage have the potential to reduce blood glucose levels, possibly through inhibition of carbohydrate-digesting enzymes and regulation of the various signaling pathways.

In Vitro Digestion and Fermentation of Different Ethanol-Fractional Polysaccharides from Dendrobium officinale: Molecular Decomposition and Regulation on Gut Microbiota.

Polysaccharides from Dendrobium officinale have garnered attention for their diverse and well-documented biological activities. In this study, we isolated three ethanol-fractionated polysaccharides from Dendrobium officinale (EPDO) and investigated their digestive properties and effects on gut microbiota regulation in vitro. The results indicated that after simulating digestion in saliva, gastric, and small intestinal fluids, three EPDOs, EPDO-40, EPDO-60 and EPDO-80, with molecular weights (Mw) of 442.6, 268.3 and 50.8 kDa, respectively, could reach the large intestine with a retention rate exceeding 95%. During in vitro fermentation, the EPDOs were broken down in a "melting" manner, resulting in a decrease in their Mw. EPDO-60 degraded more rapidly than EPDO-40, likely due to its moderate Mw. After 24 h, the total production of short-chain fatty acids (SCFAs) for EPDO-60 reached 51.2 ± 1.9 mmol/L, which was higher than that of EPDO-80. Additionally, there was an increase in the relative abundance of Bacteroides, which are capable of metabolizing polysaccharides. EPDO-60 also promoted the growth of specific microbiota, including Prevotella 9 and Parabacteroides, which could potentially benefit from these polysaccharides. Most notably, by comparing the gut microbiota produced by different fermentation carbon sources, we identified the eight most differential gut microbiota specialized in polysaccharide metabolism at the genus level. Functional prediction of these eight differential genera suggested roles in controlling replication and repair, regulating metabolism, and managing genetic information transmission. This provides a new reference for elucidating the specific mechanisms by which EPDOs influence the human body. These findings offer new evidence to explain how EPDOs differ in their digestive properties and contribute to the establishment of a healthy gut microbiota environment in the human body.

Comprehensive Assessment of Polysaccharides Extracted from Squash by Subcritical Water under Different Conditions.

The effects of subcritical water microenvironment on the physiochemical properties, antioxidant activity and in vitro digestion of polysaccharides (SWESPs) from squash were investigated. After single-factor experiments, twenty samples were successfully prepared at different extraction temperatures (110, 130, 150, 170 and 190 °C) and extraction times (4, 8, 12 and 16 min). Under a low temperature environment, the whole process was mainly based on the extraction of SWESP. At this time, the color of SWESP was white or light gray and the molecular mass was high. When the temperature was 150 °C, since the extraction and degradation of SWESP reached equilibrium, the maximum extraction rate (18.67%) was reached at 150 °C (12 min). Compared with traditional methods, the yield of squash SWESP extracted by subcritical water was 3-4 times higher and less time consuming. Under high temperature conditions, SWESPs were degraded and their antioxidant capacity and viscosity were reduced. Meanwhile, Maillard and caramelization reactions turned the SWESPs yellow-brown and produced harmful substances. In addition, different SWESPs had different effects on in vitro digestion. In brief, SWESPs prepared under different conditions have different structures and physicochemical properties, allowing the obtainment of the required polysaccharide. Our results show that squash polysaccharides prepared in different subcritical water states had good development potential and application in the food industry.

Porcine in vitro digestion and solubilization of non-starch polysaccharides in corn and wheat supplemented with xylanase and feruloyl esterase

A study evaluated porcine in vitro digestion and non-starch polysaccharide (NSP) solubilization of corn and wheat without or with xylanase alone or xylanase plus feruloyl esterase (FE). The enzymes supplied 4000 U of xylanase and 35 U of FE per kilogram of sample. Samples were digested with pepsin at a pH of 2.0 and then with pancreatin at a pH of 6.8. The digested samples were filtered to obtain unhydrolyzed residue, which was then washed using alcohol and acetone. The cereal grains (CGs) before in vitro digestion and the washed unhydrolyzed residues were analyzed for dry matter and NSP. Xylanase improved ( P < 0.05) in vitro digestibility of dry matter (IVDDM) for wheat (85% vs. 89%), but not for corn (78% vs. 79%). Addition of FE to the xylanase-supplemented CGs increased ( P < 0.05) IVDDM for both CGs, and reduced ( P < 0.05) the arabinoxylans in the unhydrolyzed residue for corn, but not for wheat. In conclusion, xylanase product used in the current study is more effective in improving the digestibility of nutrients in wheat than in corn. The FE product used in the current study can improve the efficacy of xylanase in improving the nutrient digestibility of wheat and corn.

Molecular unraveling of polysaccharide digestion in wood-feeding termites: A solid-state NMR perspective

Termites are among the most efficient organisms utilizing polysaccharides from wood and play a significant role in global carbon recycling, especially within tropical and subtropical ecosystems. Yet, the molecular details in polysaccharide degradation by termites remain largely unexplored. In this work, we have elucidated the shared and distinct molecular details in polysaccharides digestion by the higher termite Nasutitermes on poplar and the lower termite Cryptotermes on pine using high resolution solid-state nuclear magnetic resonance spectroscopy. For the first time, structural polymers are partitioned into the minor mobile and dominant rigid phases for individual examination. The mobile polysaccharides receive less structural impacts and exhibit greater digestibility compared to the rigid counterparts. While both termites effectively degrade cellulose, Nasutitermes significantly outperforms Cryptotermes in hemicellulose breakdown. In the rigid phase, cellulose is comprehensively degraded into a fragmented and more dynamically consistent structure; As Nasutitermes breaks down hemicellulose in a similar manner to cellulose, Cryptotermes selectively digests hemicellulose at its interfaces with cellulose. Additionally, crystalline cellulose undergoes selective degradation, and the digestion of amorphous cellulose might involve sugar chain detachment within microfibrils. Overall, our findings offer significant advancements and fresh perspectives on the polysaccharide digestion strategies of different termite lineages.

The concept of enzymatic disintegration of nutrients in the upper gastrointestinal tract

The aim of the study was to study the effect of salivary amylase on improving gastric protein digestion, as well as the effect of gastric protein hydrolysis on improving fat digestion. The work consisted of two parts, in the first part, in two series, the hydrolysis of proteins under the influence of gastric juice in the presence of starch and the effect of saliva amylase on the change in the total proteolytic activity of gastric juice when using substrates of a mixture of starch and proteins were investigated. In the second part of the work, the lipolytic activity of pancreatic juice with the studied proteins was studied in the presence and absence of bile. From the data obtained, it was found that the use of a mixture of starch with proteins helps to reduce the hydrolysis of proteins by gastric juice. The use of salivary amylase promotes an increase in protein hydrolysis by reducing the formation of starch-protein complexes that prevent the digestion of proteins by gastric juice. All the studied proteins, except gelatin, have an inhibitory effect on lipase in the pancreatic juice; the degree of inhibitory effect of each protein is expressed differently. It depends on their degree of digestion in gastric juice. Thus, the preliminary hydrolysis of proteins by pepsins in the stomach contributes not only to the further improvement of their hydrolysis under the influence of proteolytic enzymes of pancreatic juice, but also to the hydrolysis of fats under the influence of pancreatic lipase. It is concluded that the sequence of nutrient breakdown by enzymes of saliva, stomach and pancreas is primarily aimed at enzymatic disintegration between polysaccharides and proteins, as well as proteins and fats, in order to reduce their interaction and the formation of physical complexes. Thus, secondarily, improve the digestibility of nutrients in the upper gastrointestinal tract. The conceptual assumption of enzymatic disintegration of nutrients in the upper gastrointestinal tract allows us to substantiate the existing sequence of initial digestion of polysaccharides by saliva, as well as the initial digestion of proteins by gastric juice.

In vitro digestion and fermentation behaviors of polysaccharides from Choerospondias axillaris fruit and its effect on human gut microbiota

Choerospondias axillaris fruit has attracted more and more attention due to its various pharmacological activities, which are rich in polysaccharides. This study investigated the in vitro saliva-gastrointestinal digestion and fecal fermentation behaviors of polysaccharides from Choerospondias axillaris fruit (CAP), as well as its impact on human gut microbiota. The results showed that CAP could be partially degraded during the gastrointestinal digestion. The FT-IR spectra of the digested CAP didn't change significantly, however, the morphological feature of SEM changed to disordered flocculent and rod-like structures. 16S rRNA sequencing analysis found that after in vitro fermentation, CAP could increase the relative abundances of beneficial bacteria including Megasphaera, Megamonas and Bifidobacterium to produce short-chain fatty acids (SCFAs), while it can also reduce the abundances of harmful bacteria of Collinsella, Gemmiger, Klebsiella and Citrobacter, suggesting that CAP could modulate the composition and abundance of gut microbiota. These results implied that CAP can be developed as a potential prebiotic in the future.

In vitro gastric digestion of polysaccharides in mixed dispersions: Evaluating the contribution of human salivary α-amylase on starch molecular breakdown

The aim of this work was to investigate the impact of the addition of salivary α-amylase on starch hydrolysis in protein-containing dispersions during an in vitro digestion process. In vitro digestion provides useful insights on the fate of nutrients during gastro-intestinal transit in complex food matrices, an important aspect to consider when developing highly nutritious foods. Many foods contain polysaccharides, and as their disruption in the gastric stage is limited, salivary α-amylase is often neglected in in vitro studies. A reference study on the effect of salivary α-amylase using one of the most advanced and complex in vitro digestion models (INFOGEST) is, however, not available. Hence, this work reports the gastrointestinal breakdown of three mixed dispersions containing whey protein isolate with different polysaccharides: potato starch, pectin from citrus peel and maize starch. The latter was also studied after heating. No polysaccharide or salivary α-amylase-dependent effect on protein digestion was found, based on the free NH2 and SDS-PAGE. However, in the heat-treated samples, the addition of salivary α-amylase showed a significantly higher starch hydrolysis compared to the sample without α-amylase, due to the gelatinization of the starch granules, which improved the accessibility of the starch molecules to the enzyme. This work demonstrated that the presence of different types of polysaccharides does not affect protein digestion, but also it emphasizes the importance of considering the influence of processing on food structure and its digestibility, even in the simplest model systems.

Polysaccharides from Brasenia schreberi with Great Antioxidant Ability and the Potential Application in Yogurt.

Brasenia schreberi is a widely consumed aquatic plant, yet the knowledge regarding its bioactive components, particularly polysaccharides, remains limited. Therefore, this study aimed to optimize the extraction process of polysaccharides from B. schreberi using the response surface method (RSM). Additionally, we characterized the polysaccharides using various methods and assessed their antioxidant capabilities both in vitro and in vivo, employing cell cultures and Caenorhabditis elegans. Furthermore, these polysaccharides were incorporated into a unique yogurt formulation. Our findings demonstrated that hot water extraction was the most suitable method for extracting polysaccharides from B. schreberi, yielding samples with high sugar content, significant antioxidant capacity, and a well-defined spatial structure. Moreover, pectinase was employed for polysaccharide digestion, achieving an enzymolysis rate of 10.02% under optimized conditions using RSM. Notably, the results indicated that these polysaccharides could protect cells from oxidative stress by reducing apoptosis. Surprisingly, at a concentration of 250 μg/mL, the polysaccharides significantly increased the survival rate of C. elegans from 31.05% to 82.3%. Further qPCR results revealed that the polysaccharides protected C. elegans by up-regulating the daf-16 gene and down-regulating mTOR and insulin pathways, demonstrating remarkable antioxidant abilities. Upon addition to the yogurt, the polysaccharides significantly enhanced the water retention, viscosity, and viability of lactic acid bacteria. These outcomes underscore the potential of polysaccharides from B. schreberi as a valuable addition to novel yogurt formulations, thereby providing additional theoretical support for the utilization of B. schreberi.

Performance of growing lambs on rations containing <i>Lathyrus </i>grainsas protein source

The effect of feeding Lathyrus grain as substitute of GNC protein in the diet of lambs was studied for nutrient utilization, blood and rumen metabolites and growth performance. Jalauni lambs (n=18) weighing around 16.45±1.50 kg were randomly allocated into three dietary treatments in a completely randomized block design. In the control group (LG0), the animals were fed ad lib. green chaff of fodder Sorghum bicolor cv. M. P. Chari with concentrate mixture as per requirement whereas in the LG50 and LG100, the crude protein of groundnut cake was replaced @50% and 100% with Lathyrus grain (LG) protein in the concentrate mixture, respectively. Supplementation of LG did not influence the total DMI (g/day) in animals of different experimental groups. Digestibility(%) of DM, OM, and cell wall polysaccharides (NDF, ADF, cellulose) was also comparable amongst the different dietary groups, while CP digestibility was higher in LG50 group than LG0 or LG100 group. Digestible crude protein (DCP) content was higher in LG50 than LG0 or LG 100 whereas total digestible nutrients (TDN) contents were comparable amongst the treatment groups. Similarly, rumen metabolites and all the blood parameters were comparable among the groups and within the normal physiological range. The daily body weight gain was not affected with the experimental diets. It could be concluded that Lathyrus grain could be used as an alternative source of protein in the concentrate mixture without any adverse impacts on nutrient utilization, rumen fermentation, blood metabolites and growth performance of Jalauni lambs.

Effect of in vitro digestion and fermentation of kiwifruit pomace polysaccharides on structural characteristics and human gut microbiota

Kiwifruit pomace is abundant in polysaccharides that exhibit diverse biological activities and prebiotic potential. This study delves into the digestive behavior and fermentation characteristics of kiwifruit pomace polysaccharides (KFP) through an in vitro simulated saliva-gastrointestinal digestion and fecal fermentation. The results reveal that following simulated digestion of KFP, its molecular weight reduced by 4.7%, and the reducing sugar (CR) increased by 9.5%. However, the monosaccharide composition and Fourier transform infrared spectroscopy characteristics showed no significant changes, suggesting that KFP remained undigested. Furthermore, even after saliva-gastrointestinal digestion, KFP retained in vitro hypolipidemic and hypoglycemic activities. Subsequently, fecal fermentation significantly altered the physicochemical properties of indigestible KFP (KFPI), particularly leading to an 89.71% reduction in CR. This indicates that gut microbiota could decompose KFPI and metabolize it into SCFAs. Moreover, after 48 h of KFPI fecal fermentation, it was observed that KFPI contributed to maintaining the balance of gut microbiota by promoting the proliferation of beneficial bacteria like Bacteroides, Lactobacillus, and Bifidobacterium, while inhibiting the unfavorable bacteria like Bilophila. In summary, this study offers a comprehensive exploration of in vitro digestion and fecal fermentation characteristics of KFP, providing valuable insights for potential development of KFP as a prebiotic for promoting intestinal health.

Physicochemical characterization, digestion profile and gut microbiota regulation activity of intracellular polysaccharides from Chlorella zofingiensis

A number of studies have shown that the polysaccharides from microalgae exhibit diverse biological activities, however, little is known about their digestibility and impact on human gut microbiota. In this study, a simulating digestion and fermentation system were established to investigate the digestibility and fermentation of intracellular polysaccharides from Chlorella zofingiensis (CZIP-S3). The results indicated that CZIP-S3 is a macromolecular polysaccharide composed of mannose, glucose, galactose and rhamnose, consisting of a main chain and two branched repeating units. CZIP-S3 could not be digested in the upper gastrointestinal tract. However, CZIP-S3 could be metabolized into smaller molecules by the gut microbiota. The pH values continuously decrease during fermentation, whereas, the amount of short-chain fatty acids steadily increase. Furthermore, CZIP-S3 could modulate the composition of gut microbiota, via lowering the ratio of Firmicutes/Bacteroidetes and increasing the relative abundance of Bacteroides, Bifidobacterium and Akkermansia. The data suggested that CZIP-S3 could potentially be used as an ingredient for functional foods or prebiotics to improve human health by promoting the relative abundances of beneficial bacteria.

A dynamic model to measure retention of solid and liquid digesta fractions in chickens fed diets with differing fibre sources.

Dietary fibres impact multiple digestive processes, and insights into the effects of various types of fibre on digesta retention time are required to optimise current feed formulation systems. Therefore, the objective of this study was to apply a dynamic modelling approach to generate estimates for the retention time of solid and liquid digesta in broilers fed different fibre sources. A maize-wheat-soybean meal control diet was compared against three diets in which wheat was partially substituted with oat hulls, rice husks, or sugar beet pulp (3% w/w). Non-starch polysaccharide (NSP) digestibility was evaluated in broilers between 23 and 25days of age (n=60 birds/treatment) using titanium dioxide (TiO2, 0.5g/kg) as a marker, after feeding the experimental diets for 21days. Digesta mean retention time (MRT) was measured in another 108 birds at 30days of age by the administration of an oral pulse dose of chromium sesquioxide (Cr2O3) as solid marker and Cobalt-EDTA as liquid marker, and subsequent measurement of marker recovery in compartments of the digestive tract (n=2 or 3 replicate birds/time point/treatment). Marker recovery models to estimate fractional passage rates for solid and liquid digesta in crop, gizzard, small intestine, and caeca compartments of the gastrointestinal tract were developed to predict MRT of solid and liquid digesta for each dietary treatment. The models were composed of a series of first-order differential equations, representing the variation of marker concentration in a compartment over time. Estimated MRT of solid and liquid digesta in the gizzard varied from 20min for oat hulls and 34min for rice husks diets to 14min for sugar beet pulp and 12min for control diets. In the caeca, liquid MRT was decreased compared to the control diet (989min) for the sugar beet pulp diet (516min), while it was increased for both the oat hulls and rice husks diets (≈1 500min). Overall, these estimates are greater than those previously reported, suggesting that liquid digesta retention in the caeca previously has been underestimated. Digestibility of total NSP was increased by dietary fibre inclusion, regardless of the fibre type, although degradation of constituent sugars of NSP varied among diets. In conclusion, the inclusion of fibre sources at a low level (3% w/w) in the diet of broiler modulated retention time mainly in the gizzard and caeca, and increased digestibility of NSP.