Genome sequence data of Saccharomyces cerevisiae CBS 493.94.

Whole genome sequencing (WGS) and data concerning identity and safety for Saccharomyces cerevisiae CBS 493.94 are reported. This strain was isolated from a British brewery in 1958 and deposited at the CBS culture collection Westerdijk Fungal Biodiversity Institute under the accession number CBS 493.94. The long-reads sequencing data, obtained via PacBio Sequel, and short-reads data, via Illumina NovaSeq 6000, were deposited at NCBI under accession number PRJNA1044661. The hybrid assembly was made publicly available via Zenodo and NCBI. For strain identification, data from 18S rRNA, ANI dendrogram and Core Genome single nucleotide polymorphism (SNP) Tree showed that the present isolate belongs to the genus Saccharomyces, species cerevisiae. The potential genes of concern, e.g. antimycotic resestance genes, were not detected. This strain is commonly used as a feed additive for animal health improvement and the present data summarise the unambiguous identity and strain's FKS1 gene does not code for any amino acid variants of concern.

A Meta-Analysis of the Effects of Dietary Yeast Mannan-Rich Fraction on Broiler Performance and the Implication for Greenhouse Gas Emissions from Chicken Production.

Dietary supplementation of yeast-derived mannan-rich fraction (MRF) could improve the gastrointestinal health and production efficiency of broilers, and, consequently, lower the environmental impacts of chicken production. The objective of this meta-analysis was to quantify the retrospective effects of feeding MRF (Actigen®, Alltech Inc., Nicholasville, KY) on the production performance of broilers. The meta-analysis database included 27 studies and consisted of 66 comparisons of MRF-supplemented diets vs. basal (i.e., negative control) and antibiotic-supplemented (i.e., positive control) diets. A total of 34,596 broilers were involved in the comparisons and the average final age of the birds was 35 days. Additionally, the impact of feeding MRF on the carbon footprint (feed and total emission intensities) of chicken production was evaluated using the meta-analysis results of broiler performance (MRF vs. basal diets) to develop a scenario simulation that was analyzed by a life cycle assessment (LCA) model. A database of all trials (MRF vs. basal and antibiotic diets) indicated that feeding MRF increased (p < 0.01) average daily feed intake (ADFI; +3.7%), final body weight (FBW; +3.5%), and average daily gain (ADG; 4.1%) and improved (p < 0.01) feed conversion ratio (FCR; -1.7%) without affecting (p > 0.05) mortality. A subdatabase of MRF vs. basal diets indicated that dietary MRF increased ADFI (+4.5%), FBW (+4.7%), and ADG (+6.3%) and improved FCR (-2.2%) and mortality (-21.1%). For the subdatabase of MRF vs. antibiotic diets, both treatments exhibited equivalent effects (p > 0.05) on broiler performance parameters, suggesting that MRF could be an effective alternative to in-feed antibiotics. Subgroup analysis revealed that different study factors (year of study, breed/strain, production challenges, and MRF feeding duration) influenced the effect of dietary MRF on broiler performance. Simulated life cycle analysis (LCA) indicated that feeding MRF decreased feed and total emission intensities, on average, by -2.4% and -2.1%, respectively. In conclusion, these results demonstrate that dietary MRF is an effective nutritional solution for improving broiler performance, an effective alternative to in-feed antibiotic growth promoters, and reduces the environmental impact of poultry meat production.

Yeast mannan rich fraction positively influences microbiome uniformity, productivity associated taxa, and lay performance.

BACKGROUND: Alternatives to antibiotic as growth promoters in agriculture, such as supplemental prebiotics, are required to maintain healthy and high performing animals without directly contributing to antimicrobial resistance bioburden. While the gut microbiota of broiler hens has been well established and successfully correlated to performance, to our knowledge, a study has yet to be completed on the effect of prebiotic supplementation on correlating the mature laying hen productivity and microbiota. This study focused on establishing the impact of a yeast derived prebiotic, mannan rich fraction (MRF), on the cecal microbiota of late laying hens. This study benefitted from large sample sizes so intra- and intergroup variation effects could be statistically accounted for. RESULTS: Taxonomic richness was significantly greater at all taxonomic ranks and taxonomic evenness was significantly lower for all taxonomic ranks in MRF-supplemented birds (P < 0.005). Use of principal coordinate analyses and principal component analyses found significant variation between treatment groups. When assessed for compositional uniformity (an indicator of flock health), microbiota in MRF-supplemented birds was more uniform than control birds at the species level. From a food safety and animal welfare perspective, Campylobacter jejuni was significantly lower in abundance in MRF-supplemented birds. In this study, species associated with high weight gain (an anticorrelator of performance in laying hens) were significantly lower in abundance in laying hens while health-correlated butyrate and propionate producing species were significantly greater in abundance in MRF-supplemented birds. CONCLUSIONS: The use of prebiotics may be a key factor in controlling the microbiota balance limiting agri-food chain pathogen persistence and in promoting uniformity. In previous studies, increased α- and ß-diversity indices were determinants of pathogen mitigation and performance. MRF-supplemented birds in this study established greater α- and ß-diversity indices in post-peak laying hens, greater compositional uniformity across samples, a lower pathogenic bioburden and a greater abundance of correlators of performance.

The Effect of including a Mixed-Enzyme Product in Broiler Diets on Performance, Metabolizable Energy, Phosphorus and Calcium Retention.

The importance of enzymes in the poultry industry is ever increasing because they help to extract as many nutrients as possible from the raw material available and reduce environmental impacts. Therefore, an experiment was conducted to examine the effect of a natural enzyme complex (ASC) on diets low in AME, Ca and P. Male Ross 308 broilers (n = 900) were fed one of four diets: (1) positive control (PC) with no enzyme added (AME 12.55 MJ/kg, AVPhos 4.8 g/kg and AVCal 9.6 g/kg); (2) negative control (NC) with no enzyme added and reduced AME, Ca and P (AME 12.18 MJ/kg, AVPhos 3.3 g/kg, AVCal 8.1 g/kg); (3) negative control plus ASC at 200 g/t; and (4) negative control plus ASC at 400 g/t. Broiler performance, digesta viscosity, tibia mineralization and mineral content were analyzed at d 21. Between d 18 and 20, excreted DM, GE, total nitrogen, Ca, and P were analyzed. ASC at 200 g/t and 400 g/t improved the FCR (p = 0.0014) significantly when compared with that of the NC. There were no significant differences in BW or FI between the treatments. Birds fed ASC at 200 g/t and 400 g/t had significantly improved digesta viscosity (p < 0.0001) compared with that of the PC and NC birds and had significantly higher excreted DM digestibility (p < 0.01) than the NC and the PC birds with 400 g/t ASC. ASC inclusion significantly improved P retention (p < 0.0001) compared to that in the PC. Ca retention was significantly increased by 400 g/t ASC compared to that in the PC and NC (p < 0.001). AME was significantly higher (p < 0.0001) for all treatments compared to that in the NC. There were no significant differences between treatments for any of the bone measurements. This study showed that feeding with ASC can support the performance of broilers when fed a diet formulated to have reduced Ca, P and AME, with the greatest results being seen with a higher level of ASC inclusion.

Skin and eye irritancy assessment of six lactic acid bacteria strains.

Here we investigate the suitability of in vitro models to assess the skin and eye irritation potential of six microbial strains. Acute skin irritation was tested according to the unmodified and modified OECD test guideline (OECD TG) 439, while acute eye irritation was examined using the OECD TG 491 and 492. The OECD TG 439 guideline, modified to introduce 8-10 µg/mL of streptomycin during the recovery phase and use of test items containing 100% microbial product instead of finished formulae, was found to be suitable for skin irritation evaluation. On the other hand, the OECD TG 491 procedure was the most appropriate for evaluating eye irritation. None of the six microbial strains, namely, Lactiplantibacillus plantarum (IMI 507026, IMI 507027, IMI 507028), Lacticaseibacillus rhamnosus (IMI 507023), and Pediococcus pentosaceus (IMI 507024, IMI 507025), tested in this study caused skin or eye irritation under the study condition.

An efficient Pulsed-Field Gel Electrophoresis (PFGE) method for typing autolytic Lacticaseibacillus rhamnosus strains.

Species of lactic acid bacteria, due to their versatile metabolism, are commonly used in food and feed products, both as technological starters and as health- and welfare-promoting agents. Correct strain identification in microbe-containing products is vital, and the Pulsed-Field Gel Electrophoresis (PFGE) typing method is considered the 'gold standard' for this purpose. This typing technique is widely used in molecular epidemiology, especially for the early detection of emerging isolates with food-safety implications, for outbreak surveillance, and for infection control. The autolytic behavior that we encountered when typing Lacticaseibacillus rhamnosus strains using the PFGE technique led us to modify the current method used for typing lactic acid bacteria. This study describes a PFGE method for the molecular typing of autolytic members of the lactic acid bacteria.•An efficient method for overcoming DNA degradation during PFGE analysis for typing Lacticaseibacillus rhamnosus strains is described.•The method described herein could be considered for typing autolytic lactic acid bacteria.

The user safety assessment of a selenized yeast feed additive.

Purpose: Of the several selenized yeasts authorised for use as feed additives in the EU, Saccharomyces cerevisiae CNCM I-3060 inactivated' (Sel-Plex®), was the first to be approved for use, in 2006. The additive has a concentration of selenium between 2000 and 2400 mg/kg and a selenomethionine content greater than 63%. Previous toxicological and safety studies have shown Sel-Plex® to be safe for use for target animal species, consumers, users and the environment. A new formulation of Sel-Plex® was recently developed however, with a minimum selenium content of 3000 mg/kg. The increase in selenium in this product, Sel-Plex® 3000, presented the need to assess the risk for workers and users and to establish if there would be any eye and/or skin irritancy and skin sensitisation effects associated with the product. The purpose of this paper is to present the methodology and results of the user safety skin and eye studies performed on Sel-Plex® 3000.Materials & Methods: In vitro skin and eye models were used to assess skin and eye irritancy, while skin sensitisation was examined using an in vivo method. The acute eye irritation was evaluated using a Reconstructed human Cornea-like Epithelium (RhCE) model, which followed the OECD guideline 492. The skin irritation was assessed based on its ability to induce cell death in a commercial reconstructed human epidermis (RhE) model (EPISKIN™) according to the OECD Guideline No. 439. The skin sensitising potential was evaluated in the Guinea pig in line with OECD Guideline 406, and measured the extent and degree of skin reaction to a challenge exposure following previous topical exposure of a substance on the skin.Results: The skin and eye irritation test results showed that Sel-Plex® 3000 was a non-irritant in both cases. The skin sensitisation study showed that the additive did not generate a sensitisation response in the guinea pig and should not be considered a skin sensitiser.Conclusion: These results indicate that Sel-Plex® 3000 is safe to use for workers in an industrial setting when handling the product and the studies may be further used to support regulatory compliance in respective markets.

Meta-analysis and sustainability of feeding slow-release urea in dairy production.

Slow-release urea (SRU) is a coated non-protein nitrogen (NPN) source for providing rumen degradable protein in ruminant nutrition. A meta-analysis was conducted to evaluate the effects of replacing vegetable protein sources with SRU (Optigen®, Alltech Inc., USA) on the production performance of dairy cows. Additionally, the impact of SRU supplementation on dairy sustainability was examined by quantifying the carbon footprint (CFP) of feed use for milk production and manure nitrogen (N) excretion of dairy cows. Data on diet composition and performance variables were extracted from 17 experiments with 44 dietary comparisons (control vs. SRU). A linear mixed model and linear regression were applied to statistically analyse the effect of SRU on feed intake and production performance. Feeding SRU decreased (P < 0.05) dry matter intake (DMI, -500 g/d) and N intake (NI, -20 g/d). There was no significant effect (P > 0.05) on milk yield, fat-corrected milk, energy-corrected milk, and milk fat and protein composition. However, SRU supplementation improved (P < 0.05) feed efficiency (+3%) and N use efficiency (NUE, +4%). Regression analyses revealed that increasing SRU inclusion level decreased DMI and NI whereas increasing dietary crude protein (CP) increased both parameters. However, milk yield and feed efficiency increased in response to increasing levels of SRU inclusion and dietary CP. The NUE had a positive relationship with SRU level whereas NUE decreased with increasing dietary CP. The inclusion of SRU in dairy diets reduced the CFP of feed use for milk production (-14.5%; 373.13 vs. 319.15 g CO2 equivalent/kg milk). Moreover, feeding SRU decreased manure N excretion by 2.7% to 3.1% (-12 to -13 g/cow/d) and N excretion intensity by 3.6% to 4.0% (-0.50 to -0.53 g N/kg milk). In conclusion, feeding SRU can contribute to sustainable dairy production through improvement in production efficiency and reduction in environmental impacts.

Efficient Aflatoxin B1 Sequestration by Yeast Cell Wall Extract and Hydrated Sodium Calcium Aluminosilicate Evaluated Using a Multimodal In-Vitro and Ex-Vivo Methodology.

In this work, adsorption of the carcinogenic mycotoxin aflatoxin B1 (AFB1) by two sequestrants-a yeast cell wall-based adsorbent (YCW) and a hydrated sodium calcium aluminosilicate (HSCAS)-was studied across four laboratory models: (1) an in vitro model from a reference method was employed to quantify the sorption capabilities of both sequestrants under buffer conditions at two pH values using liquid chromatography with fluorescence detection (LC-FLD); (2) in a second in vitro model, the influence of the upper gastrointestinal environment on the mycotoxin sorption capacity of the same two sequestrants was studied using a chronic AFB1 level commonly encountered in the field (10 µg/L and in the presence of feed); (3) the third model used a novel ex vivo approach to measure the absorption of 3H-labelled AFB1 in the intestinal tissue and the ability of the sequestrants to offset this process; and (4) a second previously developed ex vivo model readapted to AFB1 was used to measure the transfer of 3H-labelled AFB1 through live intestinal tissue, and the influence of sequestrants on its bioavailability by means of an Ussing chamber system. Despite some sorption effects caused by the feed itself studied in the second model, both in vitro models established that the adsorption capacity of both YCW and HSCAS is promoted at a low acidic pH. Ex vivo Models 3 and 4 showed that the same tested material formed a protective barrier on the epithelial mucosa and that they significantly reduced the transfer of AFB1 through live intestinal tissue. The results indicate that, by reducing the transmembrane transfer rate and reducing over 60% of the concentration of free AFB1, both products are able to significantly limit the bioavailability of AFB1. Moreover, there were limited differences between YCW and HSCAS in their sorption capacities. The inclusion of YCW in the dietary ration could have a positive influence in reducing AFB1's physiological bioavailability.

A Meta-Analysis of the Effects of Slow-Release Urea Supplementation on the Performance of Beef Cattle.

Slow-release urea (SRU) is a coated non-protein nitrogen (NPN) source for ruminant nutrition. This study applied a meta-analytic technique to quantify the effect of a commercial SRU (Optigen®, Alltech Inc., Nicholasville, KY, USA) on the performance of beef cattle. Data were extracted from 17 experiments and analysed using the random-effects model to estimate the effect size of SRU on dry matter intake (DMI), crude protein intake (CPI), live weight gain (LWG) and feed efficiency (FE) of growing and finishing beef cattle. There was no effect of feeding SRU on the overall DMI and CPI of beef cattle. Dietary inclusion of SRU improved the overall LWG (+92 g/d/head) and FE (+12 g LWG/kg DMI/head) of beef cattle. Notably, SRU supplementation in growing cattle exhibited a better improvement on LWG (130 vs. 60 g/d/head) and FE (18 vs. 8 g LWG/kg DMI/head) compared with finishing cattle. Moreover, SRU showed consistent improvements on the LWG and FE of beef cattle under several study factors. Simulation analysis indicated that positive effects of SRU on LWG and FE improved profitability through reduction in feed cost and reduced the emission intensity of beef production. These results indicate that SRU is a sustainable NPN solution in beef cattle production.

Design and validation of a real-time PCR technique for assessing the level of inclusion of fungus- and yeast-based additives in feeds.

A reliable method for quantification of non-viable microbe-based nutritional and zootechnical additives introduced into feed is essential in order to ensure regulatory compliance, feed safety and product authenticity in industrial applications. In the present work, we developed a novel real-time quantitative polymerase chain reaction (qPCR) -based analysis protocol for monitoring two microbial additives in feed matrices. To evaluate the applicability of the method, pelleted wheat- and maize-based broiler chicken diets containing a non-viable phytase-producing strain of Aspergillus niger produced in solid state fermentation (150 or 300 g/t) and a non-viable selenium-enriched Saccharomyces cerevisiae (100 or 200 g/t) as model feed ingredients, were manufactured and subjected to analysis. Power analysis of the qPCR results indicated that 2 to 6 replicate feed samples were required to distinguish the product doses applied, which confirms that the microbial DNA was efficiently recovered and that potential PCR inhibitors present in the feed material were successfully removed in DNA extraction. The analysis concept described here was shown to be an accurate and sensitive tool for monitoring the inclusion levels of non-viable, unculturable microbial supplements in animal diets.

Conversion of Branched-Chain Amino Acids to Corresponding Isoacids - An in vitro Tool for Estimating Ruminal Protein Degradability.

In this paper we describe a study that evaluates the applicability of an in vitro fermentation model to assess the resistance of protein supplements to rumen degradation. The protein sources used were: soybean meal (SBM); whey protein (WHEY), which was expected to be rapidly degraded, and yeast-derived microbial protein (YMP), which was proposed to be resistant to rumen degradation. The basal diet was composed of grass silage and a commercial compound feed. The protein supplements were added at three isonitrogenous doses. Fermentation was monitored for 24 h and gas production, volatile fatty acids, lactic acid, and ammonia were analyzed at three timepoints. Protein degradation was estimated by determining the extent to which branched-chain amino acids (BCAA) introduced with the protein supplement were converted to corresponding branched-chain volatile fatty acids (BCVFA). At the highest dose of WHEY, 60% of introduced valine, leucine, and isoleucine was recovered as isobutyric, 2-methylbutyric, and isovaleric acid (products of BCAA decarboxylation and deamination), respectively. The BCVFA detected represented 50% of added BCAA with SBM, but <15% with YMP. Further indications that YMP protein is resistant to degradation were provided by analysis of ammonia. With YMP, the residual ammonia concentration only marginally exceeded that of the cultures with no protein supplementation, while it increased dose-dependently when the vessels were supplemented with WHEY or SBM. This suggests that with WHEY and SBM, the rate of deamination exceeded the rate of ammonia assimilation by bacteria. Residual ammonia and BCVFA, the two indicators of protein fermentation, were strongly correlated. Overall bacterial activity was monitored as yield of gas, volatile fatty acids, and bacteria. These three correlating parameters showed that WHEY only modestly stimulated fermentation, whereas SBM and YMP stimulated fermentation extensively, possibly owing to their higher carbohydrate content. The results presented suggest that the in vitro fermentation method was suitable for detecting differences in resistance of protein supplements to rumen degradation and following a full method validation could be a useful tool for diet formulation. The data obtained suggested that YMP was the most resistant and WHEY the most susceptible to degradation.

Whole-Life or Fattening Period Only Broiler Feeding Strategies Achieve Similar Levels of Omega-3 Fatty Acid Enrichment Using the DHA-Rich Protist, Aurantiochytrium limacinum.

The fatty acid composition of broiler chicken tissues can be increased by adding omega-3 rich ingredients to their diets. The purpose of this study was to compare the levels of tissue enrichment observed following the supplementation of broilers with the docosahexaenoic acid (DHA)-rich protist, Aurantiochytrium limacinum (AURA) for their whole life (42 days) or for the final 21-day fattening period. Day-old chicks (n = 350) were distributed among 35 pens (10 birds per pen) with each pen randomly assigned to one of five treatments: Control; 0.5% AURA from day 0-42; 1% AURA from day 0-42; 0.5% AURA from day 21-42; 1% AURA from day 21-42. Production parameters were recorded over the course of the study and the fatty acid profile of the breast, thigh, liver, kidney and skin with adhering fat was quantified at the end of the feeding period. The level of supplementation had a significant impact on the degree of omega-3 tissue enrichment, however, no differences were observed when the same dose was provided for 21 or 42 days. These results indicate that supplementation with AURA for a period of 21 days does not negatively affect broiler productivity and is the most efficient strategy to increase the nutritional value of broiler products.

Tolerance of Broilers to Dietary Supplementation with High Levels of the DHA-Rich Microalga, Aurantiochytrium Limacinum: Effects on Health and Productivity.

It is well established that the docosahexaenoic acid (DHA) content of commonly consumed meats, such as chicken, can be increased through dietary supplementation with DHA-rich ingredients. The purpose of this study was to investigate the tolerance of broilers to dietary supplementation with the unextracted biomass of a DHA-rich microalgae Aurantiochytrium limacinum, so as to ensure its safety, since it is accumulated in broiler meat. Healthy day-old male Ross 308 chicks (n = 1120) were evenly distributed to 32 pens (35 chicks per pen), with pens randomly allocated to one of four dietary treatments, each having eight replicates. The dietary groups included one untreated control and three treatments corresponding to three inclusion levels (0.5, 2.5, and 5.0%) of All-G-Rich®, with the birds receiving the experimental diets ad libitum during the study (day 0⁻42). Bird survival, blood parameters, productivity, and breast and thigh DHA content were determined after 42 days of feeding. Supplementation at up to 10 times the intended use level had no negative effects on the mortality, blood parameters or productivity of the birds, while significant increases in the meat DHA content were observed. These results indicate that supplementation with Aurantiochytrium limacinum is a safe and effective way to increase broiler tissue DHA content.

Dietary supplementation of finishing pigs with the docosahexaenoic acid-rich microalgae, Aurantiochytrium limacinum: effects on performance, carcass characteristics and tissue fatty acid profile.

OBJECTIVE: The aim of this experiment was to evaluate the effect of dietary supplementation with the docosahexaenoic acid (DHA)-rich microalgae, Aurantiochytrium limacinum (AURA) on pig performance, carcass traits, and the fatty acid composition of pork Longissimus lumborum (LL) and backfat. METHODS: A total of 144 Pig Improvement Company (PIC)×Goland finishing pigs (72 females and 72 castrated males) of mean weight 117.1 (±13.1) kg were blocked by sex and body weight and provided with 0% or 1% AURA in isonutritive and isocaloric diets. A total of 24 pens provided 12 replicates per treatment. Animals were weighed on day 0 and 28 with feed and water intake recorded per pen. After 31 days supplementation (28 days of study and 3 days until the slaughtering date) three animals per pen (n = 72) were slaughtered and the LL and backfat thickness, lean meat content and dressing percentage were recorded for the carcasses. The fatty acid (FA) profile of the LL and backfat was established by direct FA methyl ester synthesis. RESULTS: No differences were observed for any performance parameters or carcass traits. Supplementation with AURA resulted in significant changes to the FA profiles of both the LL and backfat with male and female pigs responding differently to supplementation in terms of particular FAs. Overall, pork LL samples had significantly higher eicosapentaenoic acid (p<0.001) and DHA concentrations (p<0.001), and higher omega-3 (n-3) FAs (p<0.001), as well as an increased omega3:omega6 (n-3:n-6) ratio (p = 0.001). For backfat, supplementation resulted in significantly higher amounts of DHA (p<0.001) and n-3 FAs (p<0.001). CONCLUSION: These results indicate that dietary supplementation with 1% AURA over a 31 day period can increase the FA composition of pork LL and backfat, specifically the DHA, with no major impact on growth performance and carcass traits.

Fermentation of wheat: effects of backslopping different proportions of pre-fermented wheat on the microbial and chemical composition.

The objective of the study was to examine effect of backslop on the chemical and microbiological characteristics of fermented wheat (FW). Coarsely ground wheat was mixed with water (1:3 wt/wt) and inoculated with 6 log cfu ml(-1) each of an overnight culture of Lactobacillus plantarum and Pediococcus pentosaceus. Four fermentation treatments were conducted in 45 1, closed, PVC containers over 48 hours. Three treatments investigated the benefits of the addition of previously fermented wheat (backslopping, BSL) at different proportions (0.20, 0.33 or 0.42 kg) to freshly prepared wheat. The control treatment contained no addition of BSL. Elimination of coliforms from the FW within 48 h was only achieved through backslopping; where coliform bacteria counts decreased from approximately 6.5 log10 cfu ml(-1) to less than 3 log10 cfu ml(-1). There was no apparent advantage in increasing the backslop proportion above 0.20. However, the exclusion of coliform bacteria required the pH to remain below 4.0 for at a minimum of 24 h. The results of these studies indicate that fermentation of wheat has the potential to reduce the risk of feed-borne colibacillosis and provides a practical alternative to producers that cannot ferment multiple diets or have limited fermentation capacity.

Natural and modified (1-->3)-beta-D-glucans in health promotion and disease alleviation.

A number of polysaccharides with beta-glycosidic linkage are widespread in nature in a variety of sources. All have a common structure and the (1-->3)-beta-D-glucan backbone is essential. They have attracted attention over the years because of their bioactive and medicinal properties. In many cases their functional role is a mystery, in others it is well established. Because of their insoluble chemical nature, particulate (1-->3)-beta-D-glucans are not suitable for many medical applications. Various methods of changing or modifying the beta-D-glucan chemical structure and transforming it to a soluble form have been published. The beta-D-glucan bioactive properties can be affected positively or negatively by such modifications. This review examines beta-glucan sources in nature, health effects and structure-activity relationships. It presents the current state of beta-D-glucan solubilization methods and discusses their effectiveness and application possibilities for the future.