A review of 733 published trials on Bio-Mos®, a mannan oligosaccharide, and Actigen®, a second generation mannose rich fraction, on farm and companion animals

Early-life supplementation with mannan-rich fraction to regulate rumen microbiota, gut health, immunity, and growth performance in dairy goat kids

Enhancing gastrointestinal health, immunity, and digestion are key factors to support dairy goat kid performance. Several additives have been studied in relation to these actions. This study investigated the impact of mannan-rich fraction (MRF) inclusion in goat milk on the growth performance, gut health, rumen fermentation, and microbial profiles of Xinong Saanen dairy goat kids. A total of 80 kids aged 14 d and 4.72 ± 0.33 kg BW were randomly assigned into 2 groups: control and MRF (1 g/d MRF mixed into milk). Each group consisted of 40 kids with 10 kids per pen. All kids were given milk individually and fed a starter diet by pen, with the trial lasting 10 wk. Body weight and blood samples were collected on the seventh day at 2, 6, 10 and 12 wk of age, and feed intake was determined daily. From the first to seventh day at 12 wk of age, fecal samples were collected from 4 kids in each group to analyze nutrient digestibility. On the seventh day of 12 wk of age, 4 kids from each group were slaughtered for evaluation of rumen fermentation, rumen microbiota, and gut morphology. The results indicated that MRF supplementation led to greater overall BW, overall starter DMI, and overall ADG, along with a lower overall diarrhea rate. However, no difference in overall feed efficiency and apparent digestibility of nutrients was observed. Furthermore, MRF supplementation resulted in increased ileal villus height; higher RNA expression of claudin-1 and occludin in the duodenum; higher expression of ZO-1, JAM-2, and occludin in the jejunum; and higher expression of claudin-1, JAM-2, and occludin in the ileum. Additionally, the concentrations of overall IgA, overall IgM, and overall IgG were higher in the MRF group. The concentrations of ruminal acetate and total volatile fatty acid were higher with MRF supplementation (P < 0.05). Meanwhile, supplementation with MRF resulted in higher abundance of Bacteroidetes and Succinivibrio and lower abundance of Firmicutes and Succiniclasticum in the rumen. Overall, the growth performance, gut health, immunity, and ruminal microbial structure of dairy goat kids benefited from MRF supplementation.

Mannan oligosaccharides as a prebiotic for laying hens: effects on fertility, hatchability, productive performance, and immunity

This experiment examined how adding mannan-oligosaccharides (MOS) to the diet affected fertility, hatching rates, egg production, carcass characteristics, cost-effectiveness, and immune function in laying hens. One hundred and twenty Mandarah chickens (30 hens and 3 roosters per group) were randomly chosen between 34 and 50 wk old and divided into four groups. The first group was the control group, which was given just the basal diet. The basal diet was given to the second, third, and fourth experimental groups along with three different levels of MOS (0.1, 0.2, and 0.5 g/kg diet, respectively). Results found that hens fed MOS at various levels laid eggs at a significantly higher rate, enhanced egg number, egg mass and feed conversion ratio than the control group (P < 0.05). MOS seemed to improve carcass quality. The best results for egg quality (Haugh unit) and testosterone levels were seen with a dose of 0.5 g/kg of MOS compared to the control birds (P < 0.05). All MOS levels led to higher estradiol-17β (E2) levels and better economic efficiency (EE). MOS also improved the hens' immune systems as compared to the control group. Hens-fed MOS had significantly greater levels of antibodies against Influenza viruses (H9N2) and Infectious Bronchitis Virus (P < 0.05). Also, the spleen and thymus gland, both crucial immune system components, were slightly larger (P < 0.05). It's important to note that fertility rates, hatchability, and embryo mortality rates remained similar across all groups. So, our findings suggest that incorporating MOS into the birds' diet enhances their productivity, strengthens their immune system, improves EE, and contributes to the overall health of the hens.

Breaking the Cycle: A Yeast Mannan-Rich Fraction Beneficially Modulates Egg Quality and the Antimicrobial Resistome Associated with Layer Hen Caecal Microbiomes under Commercial Conditions

Antibiotics and antibiotic growth promoters have been extensively employed in poultry farming to enhance growth performance, maintain bird health, improve nutrient uptake efficiency, and mitigate enteric diseases at both sub-therapeutic and therapeutic doses. However, the extensive use of antimicrobials in poultry farming has led to the emergence of antimicrobial resistance (AMR) in microbial reservoirs, representing a significant global public health concern. In response, non-antibiotic dietary interventions, such as yeast mannan-rich fraction (MRF), have emerged as a promising alternative to modulate the gut microbiota and combat the AMR crisis. This study investigated whether a yeast mannan-rich fraction containing feed supplement impacted the performance of laying hens, their microbiomes, and the associated carriage of antimicrobial resistance genes under commercial conditions. High-throughput DNA sequencing was utilised to profile the bacterial community and assess changes in the antibiotic resistance genomes detected in the metagenome, the "resistome", in response to MRF supplementation. It was found that supplementation favourably influenced laying hen performance and microbial composition. Notably, there was a compositional shift in the MRF supplemented group associated with a lower relative abundance of pathobionts, e.g., Escherichia, Brachyspira and Trueperella, and their AMR-encoded genes, relative to beneficial microbes. Overall, the findings further demonstrate the ability of prebiotics to improve laying hen performance through changes associated with their microbiome and resistome.

A new approach: preventive protocols with yeast products and essential oils can reduce the in-feed use of antibiotics in growing-finishing pigs

The objective of this study was to evaluate the effects of yeast products (YP) and essential oils (EO) in total or partial replacement to in-feed antibiotic protocols (growth promoter and prophylactic), both in recommended doses and in overdose of prophylactic antibiotics (PA), on growth performance, and diarrhea incidence in the growing-finishing pigs; and fecal microbiota in market hogs. Four hundred pigs (20.36 ± 2.64 kg) were assigned to five treatments in a randomized block design: diets with prophylactic and growth promoter antibiotics (ANT); ANT with 30% more PA (ANT+30); diets with less PA and YP (ANT+Y); diets with less PA, YP and EO (ANT+Y+EO); and antibiotics-free diets with YP and EO (Y+EO). The content of the active components of the YP was 60% purified β-1,3/1,6-glucans extracted from Saccharomyces cerevisiae yeast (Macrogard), 20% functional water-soluble MOS (HyperGen), and 18% MOS, extracted from Saccharomyces cerevisiae yeast (ActiveMOS). From 0 to 14 d, pigs of the ANT+30, ANT+Y, and ANT+Y+EO treatments showed a greater body weight (BW) and average daily gain (ADG) compared to pigs from the Y+EO group. From 14 to 35 d, pigs of ANT+30 and ANT+Y+EO treatments were heavier than Y+EO group. At 105 d, ANT pigs had a higher BW than the Y+EO group. For the entire period, ADG of ANT pigs was greater, and feed conversion ratio better than Y+EO pigs. From 0 to 35 d, pigs of the Y+EO treatment showed a higher diarrhea incidence compared to pigs of the other groups. From 49 to 70 d, ANT+Y and ANT+Y+EO treatments showed a lower diarrhea incidence than Y+EO group, which remained the case during the overall period. At 105 d, the alpha diversity of fecal microbiota by Shannon Entropy was lower in ANT, ANT+30, and Y+EO groups than observed for ANT+Y+EO group. The abundance of Firmicutes phylum and Firmicutes/Bacteroidetes ratio was higher in ANT than in ANT+Y+EO pigs. Proteobacteria phylum abundance in ANT+Y+EO was higher than ANT, ANT+Y, and Y+EO. Peptostreptococcaceae family abundance was higher in ANT, ANT+30, and ANT+Y groups than in ANT+Y+EO and Y+EO groups. ANT+Y+EO and Y+EO groups show a lower abundance of SMB53 genus than ANT and ANT+30 groups. In conclusion, the use of YP and EO, in partial replacement to the in-feed antibiotic protocols, does not reduce the growth performance, can replace antibiotic growth promotors, and reduce the in-feed use of PA in growing-finishing pigs. The use of YP and EO, together with PA, increases the microbial diversity, despite having important genera for weight gain in less abundance. Overdose of PA does not improve growth performance and reduces microbial diversity, which does not characterize it as an efficient preventive protocol.

Feeding a Novel Mannan-Rich Yeast Carbohydrate Product Improves Production Performance and Humoral Immunity of Broiler Chickens

The current study examined the benefits of a novel mannan-rich yeast carbohydrate product (YM) on broiler chicken growth performance and immune response against sheep red blood cells (SRBCs). A total of 144 newly hatched male Cornish cross broiler chicks were randomly assigned to four treatments with 12 cages per treatment and three birds per cage. The treatments were (1) control, basal diet; (2) YCW, basal diet + 1 g/kg yeast cell wall; (3) YM1, basal diet + 0.5 g/kg of a novel yeast mannan-rich product (YM); and (4) YM2, basal diet + 1 g/kg YM. Growth performance was measured at 14, 28, and 35 days of age (d). At 26 and 27 d, nine birds per treatment were immunized intravenously with SRBCs, and antibody responses against SRBCs were analyzed through a hemagglutination assay 7 days post-inoculation. Supplementing YM tended to improve broiler chicken weight gain from 29 to 35 d (p = 0.053). An improvement in the feed conversion ratio (FCR) was observed in the birds fed YM diets during 29-35 d and over the entire experimental period (0-35 d; p < 0.05). Furthermore, birds fed YM2 diets had more robust antibody responses against SRBCs than the control birds (p = 0.033). In conclusion, dietary supplementation of YM improved broiler chicken growth performance and antibody response against SRBCs.

Effects of dietary yeast mannan-rich fraction supplementation on growth performance, intestinal morphology, and lymphoid tissue characteristics in weaned piglets challenged with Escherichia Coli F4

We evaluated the effects of supplementing yeast mannan-reach-fraction on growth performance, jejunal morphology and lymphoid tissue characteristics in weaned piglets challenged with E. Coli F4. A total of 20 crossbred piglets were used. At weaning, piglets were assigned at random to one of four groups: piglets challenged and fed the basal diet supplemented with yeast mannan-rich fraction (C-MRF, n = 5); piglets challenged and fed the basal diet (C-BD, n = 5); piglets not challenged and fed the basal diet supplemented with yeast mannan-rich fraction (NC-MRF, n = 5), and piglets not challenged and fed the basal diet (NC-BD). Each dietary treatment had five replicates. On days 4, 5 and 10, piglets were orally challenged with 108 CFU/mL of E. Coli F4. C-MRF piglets had higher BW (p = 0.002; interactive effect) than C-BD piglets. C-MRF piglets had higher (p = 0.02; interactive effect) ADG in comparison with C-BD piglets. C-MRF piglets had higher (p = 0.04; interactive effect) ADFI than C-BD piglets. The diameter of lymphoid follicles was larger (p = 0.010; interactive effect) in the tonsils of C-MRF piglets than C-BD piglets. Lymphoid cells proliferation was greater in the mesenteric lymphnodes and ileum (p = 0.04 and p = 0.03, respectively) of C-MRF piglets. A reduction (p > 0.05) in E. Coli adherence in the ileum of piglets fed MRF was observed. In conclusion, the results of the present study demonstrate that dietary yeast mannan-rich fraction supplementation was effective in protecting weaned piglets against E. Coli F4 challenge.

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 cell wall mannan structural features, biological activities, and production strategies

Mannan and outer structural yeast cell wall polysaccharides have recently garnered attention for their health defense and cosmetic applications. In addition, many studies have confirmed that yeast cell wall mannans exhibit various biological activities, such as antioxidant, immune regulation, reducing hyperlipidemia, and gut health promotion. This paper elucidates yeast cell wall mannan structural features, biological activities, underlying molecular mechanisms, and biosynthesis. Moreover, mannan-overproducing strategies through yeast strain engineering are emphasized and discussed. This review will provide a scientific basis for yeast cell wall mannan research and industrial applications.

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 β-diversity indices were determinants of pathogen mitigation and performance. MRF-supplemented birds in this study established greater α- and β-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 Impact of a Proprietary Blend of Yeast Cell Wall, Short-Chain Fatty Acids, and Zinc Proteinate on Growth, Nutrient Utilisation, and Endocrine Hormone Secretion in Intestinal Cell Models

In piglets, it is observed that early weaning can lead to poor weight gain due to an underdeveloped gastrointestinal (GI) tract, which is unsuitable for an efficient absorption of nutrients. Short-chain fatty acids (SCFAs) such as butyrate have demonstrated their ability to improve intestinal development by increasing cell proliferation, which is vital during this transition period when the small and large intestinal tracts are rapidly growing. Previous reports on butyrate inclusion in feed demonstrated significantly increased feed intakes (FIs) and average daily gains (ADGs) during piglet weaning. Similar benefits in piglet performance have been observed with the inclusion of yeast cell wall in diets. A proprietary mix of yeast cell wall, SCFAs, and zinc proteinate (YSM) was assessed here in vitro to determine its impact on cellular growth, metabolism and appetite-associated hormones in ex vivo small intestinal pig cells and STC-1 mouse intestinal neuroendocrine cells. Intestinal cells demonstrated greater cell densities with the addition of YSM (150 ppm) compared to the control and butyrate (150 ppm) at 24 h. This coincided with the higher utilisation of both protein and glucose from the media of intestinal cells receiving YSM. Ghrelin (an appetite-inducing hormone) demonstrated elevated levels in the YSM-treated cells on a protein and gene expression level compared to the cells receiving butyrate and the control, while satiety hormone peptide YY protein levels were lower in the cells receiving YSM compared to the control and butyrate-treated cells across each time point. Higher levels of ghrelin and lower PYY secretion in cells receiving YSM may drive the uptake of protein and glucose, which is potentially facilitated by elevated gene transporters for protein and glucose. Greater ghrelin levels observed with the inclusion of YSM may contribute to higher cell densities that could support pig performance to a greater extent than butyrate alone.

Growth Performance, Metabolomics, and Microbiome Responses of Weaned Pigs Fed Diets Containing Growth-Promoting Antibiotics and Various Feed Additives

The objective of this study was to determine the potential biological mechanisms of improved growth performance associated with potential changes in the metabolic profiles and intestinal microbiome composition of weaned pigs fed various feed additives. Three separate 42 day experiments were conducted to evaluate the following dietary treatments: chlortetracycline and sulfamethazine (PC), herbal blends, turmeric, garlic, bitter orange extract, sweet orange extract, volatile and semi-volatile milk-derived substances, yeast nucleotide, and cell wall products, compared with feeding a non-supplemented diet (NC). In all three experiments, only pigs fed PC had improved (p < 0.05) ADG and ADFI compared with pigs fed NC. No differences in metabolome and microbiome responses were observed between feed additive treatments and NC. None of the feed additives affected alpha or beta microbiome diversity in the ileum and cecum, but the abundance of specific bacterial taxa was affected by some dietary treatments. Except for feeding antibiotics, none of the other feed additives were effective in improving growth performance or significantly altering the metabolomic profiles, but some additives (e.g., herbal blends and garlic) increased (p < 0.05) the relative abundance of potentially protective bacterial genera that may be beneficial during disease challenge in weaned pigs.

The Effect of Dietary Supplementation with Probiotic and Postbiotic Yeast Products on Ewes Milk Performance and Immune Oxidative Status

The administration of yeast products as feed additives has been proven to beneficially affect animal productivity through energy, oxidative, and immune status improvement. This study evaluated a combination of Saccharomyces cerevisiae live yeast (LY) with yeast postbiotics (rich in mannan-oligosaccharides (MOS) and beta-glucans) and selenium (Se)-enriched yeast on ewes' milk performance and milk quality, energy and oxidative status, and gene expression related to their immune system during the peripartum period. Ewes were fed a basal diet (BD; F:C = 58:42 prepartum and 41:59 postpartum) including inorganic Se (CON; n = 27), the BD supplemented with a LY product, and inorganic Se (AC; n = 29), as well as the combination of the LY, a product of yeast fraction rich in MOS and beta-glucans, and organic-Se-enriched yeast (ACMAN; n = 26) from 6 weeks prepartum to 6 weeks postpartum. The β-hydroxybutyric acid concentration in the blood of AC and ACMAN ewes was lower (compared to the CON) in both pre- and postpartum periods (p < 0.010). Postpartum, milk yield was increased in the AC and ACMAN Lacaune ewes (p = 0.001). In addition, the activity of superoxide dismutase (p = 0.037) and total antioxidant capacity (p = 0.034) measured via the 2,2-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) method was increased in the blood plasma of the ACMAN postpartum. Higher ABTS values were also found (p = 0.021), while protein carbonyls were reduced (p = 0.023) in the milk of the treated groups. The relative transcript levels of CCL5 and IL6 were downregulated in the monocytes (p = 0.007 and p = 0.026 respectively), and those of NFKB were downregulated in the neutrophils of the ACMAN-fed ewes postpartum (p = 0.020). The dietary supplementation of ewes with yeast postbiotics rich in MOS and beta-glucans, and organic Se, improved energy status, milk yield and some milk constituents, and oxidative status, with simultaneous suppression of mRNA levels of proinflammatory genes during the peripartum period.

Potential benefits of yeast Saccharomyces and their derivatives in dogs and cats: a review

Yeast Saccharomyces and its derivatives have been largely used in livestock and poultry nutrition for their potential positive impact on growth, performance, and general health. Originally included in animal diets as a source of protein, yeasts can also offer a wide range of by-products with interesting bioactive compounds that would confer uses beyond nutrition. Although its supplementation in livestock, poultry and even in humans is well documented, the available body of literature on the use of yeast and its derivatives in companion animals' food, mainly dogs and cats' diets, is still developing. Despite this, gut microbiota modulation, immune system enhancement or decreasing of potentially pathogenic microorganisms have been reported in pets when using these products, highlighting their possible role as probiotics, prebiotics, and postbiotics. This review attempts to provide the reader with a comprehensive on the effects of Saccharomyces and its derivatives in pets and the possible mechanisms that confer their functional properties.

The Efficacy of Yeast Supplementation on Monogastric Animal Performance-A Short Review

Due to a continual growth in the world's population and the prohibition of antibiotics in animal production, the livestock industry faces significant challenges in the global demand for meat, eggs, and dairy products. The growing demand for organic products and the prohibition on antibiotic growth promoters (AGPs) have compelled animal nutrition experts to search for natural substitutes that include medical plants and beneficial microorganisms. Natural feed additives like probiotics are found to be more effective than AGPs in reducing the load of harmful intestinal pathogens. One of the probiotics that has generated considerable interest since ancient times is yeast. Yeast is used as a supplement in animal feeds due to its relatively high protein, amino acid, energy, and micronutrient content. Yeast byproducts such as yeast cells and cell walls contain nutraceutical compounds (i.e., β-glucans, mannooligosaccharides, and nucleotides) and have been shown to improve animal growth performance and health. Though the application of yeast supplements has been reviewed to date, only a scarce amount of information exists on the yeast-derived products in non-ruminant nutrition. Additionally, it is difficult for nutritionists to differentiate the characteristics, composition, and optimal feeding among the diverse number of yeast-containing products. Due to the increasing popularity of using yeast-based products in animal feeds, the development of analytical approaches to estimate yeast and its components in these products is greatly needed. Thus, in this review, we intend to provide current knowledge of different categories of commercially available yeast and yeast-derived additives, along with their role in improving animal growth performance and health, their proposed mechanisms of action, and the challenges of quantifying yeast content and biologically active components.

Effect of drying technology in Saccharomyces cerevisiae mannans: Structural, physicochemical, and functional properties

Mannans are polysaccharides whose physicochemical and biological properties render them commercialization in several products. Since these properties are strongly dependent on production conditions, the present study aims to assess the impact of different drying technologies - freeze (FDM) and spray drying (SDM) - on the structural, physicochemical, and biological properties of mannans from Saccharomyces cerevisiae. Structural analysis was assessed by FT-IR, PXRD and SEM, whereas physicochemical properties were evaluated based on sugars, protein, ash and water contents, solubility, and molecular weight distribution. Thermal behaviour was analysed by DSC, and antioxidant activity by DPPH and ABTS assays. The parameters which revealed major differences, in terms of structural and physicochemical properties regarded morphology (SEM), physical appearance (colour), moisture (3.6 ± 0.1 % and 11.9 ± 0.6 % for FDM and SDM, respectively) and solubility (1 mg/mL for FDM and 25 mg/mL for SDM). Nevertheless, these differences were not translated into the antioxidant capacity.

Effects of Dietary Supplementation of L-Carnitine and Mannan-Oligosaccharides on Growth Performance, Selected Carcass Traits, Content of Basic and Mineral Components in Liver and Muscle Tissues, and Bone Quality in Turkeys

The study aimed to determine the effect of L-carnitine and Bio-Mos administration on selected production performance, slaughter parameters, elemental and mineral content of liver, breast and thigh muscles, and physical, morphometric, strength and bone mineral composition parameters of turkeys. The experiment was conducted on 360 six-week-old Big-6 turkey females, randomly divided into three groups of 120 birds each (six replicates of 20 birds). The turkeys of the control group were fed standard feed without additives; group II was fed with drinking water, a preparation containing L-carnitine at a dose of 0.83 mL/L, while group III was provided mixed feed with 0.5% Bio-Mos. The addition of L-carnitine and Bio-Mos increased body weight at 16 weeks (p = 0.047) and reduced the proportion of fat in the breast muscle (p = 0.029) and liver (p = 0.027). It also modified the content of some minerals in breast muscle, thigh muscle, liver, and bone. Furthermore, the addition of L-carnitine and Bio-Mos increased bone mass and length and modified the value of selected morphometric and strength parameters. The results indicate a positive effect of the applied feed additives on selected rearing indices and carcass quality while improving the elasticity and fracture toughness of the femur. There is a need for further research to determine optimal doses of L-carnitine and Bio-Mos in poultry nutrition.

Yeast Cell Wall Compounds on The Formation of Fermentation Products and Fecal Microbiota in Cats: An In Vivo and In Vitro Approach

The effects of yeast cell wall compounds (YCWs) being added to cat food on hindgut fermentation metabolites and fecal microbiota were assessed in in vivo Experiment 1 (Exp. 1) and in vitro Experiments 2 and 3 (Exp. 2 and 3). In Exp. 1, the cats' diets were supplemented with two dietary concentrations (46.2 and 92.4 ppm) of YCWs (YCW-15 and YCW-30, respectively), and a negative control diet with no compound in three groups (six cats per group) was used to assess the fecal score, pH, digestibility, fermentation products, and microbiota. In Exp. 2, feces from the cats that were not supplemented with YCWs (control) were used as an inoculum. A blend of pectin, amino acids, and cellulose was used as a substrate, and the YCW compound was added at two levels (5 and 10 mg). In Exp. 3, feces from cats fed YCWs were used as an inoculum to test three different substrates (pectin, amino acids, and cellulose). In Exp. 2 and 3, the gas production, pH, and fermentation products (ammonia, SCFAs, and BCFAs) were assessed. YCW-30 resulted in a higher digestibility coefficient of the crude protein, organic matter (OM) (p < 0.05), and energy of the diet (p < 0.10). Regarding the fermentation products, YCW-15 showed a trend toward higher concentrations of propionate, acetate, lactate, ammonia, isobutyrate, and valerate, while YCW-30 showed a trend (p < 0.10) toward higher levels of butyrate and pH values. The bacteroidia class and the genus Prevotella were increased by using YCW-30 and the control. At the gender level, decreased (p < 0.01) Megasphaera was observed with YCW inclusion. The microbiota differed (p < 0.01) among the groups in their Shannon indexes. For beta diversity, YCW-30 showed higher indexes (p = 0.008) than the control. The microbiota metabolic profile differed in the pathway CENTFERM-PWY; it was more expressed in YCW-30 compared to the control. In Exp. 2, the YCWs showed a higher ratio (p = 0.006) of the fermentation products in the treatments with additives with a trend towards a high dose of the additive (10 mg). In Exp. 3, the effects of the substrates (p < 0.001), but not of the YCWs, on the fermentation products were observed, perhaps due to the low dietary concentrations we used. However, the marked responses of the fermentation products to the substrates validated the methodology. We could conclude that the YCWs, even at low dietary concentrations, affected fecal SCFA production, reduced the fecal pH, and modulated the fecal microbiota in the cats. These responses were more pronounced under in vitro conditions.

Mannan based prebiotics modulate growth rate and energy phenotype of tetracycline resistant E. coli

Unsustainable antimicrobial use in industrial agriculture has contributed to the rise in antimicrobial resistance and there is an urgent need to find alternative and more sustainable strategies to traditional antimicrobials. Prebiotics, such as mannan-rich fraction (MRF), a cell wall product from Saccharomyces cerevisiae, have demonstrated an ability to alter the growth of antibiotic susceptible and resistant Escherichia coli and improve the efficacy of antibiotics through modulation of cellular activity. In this study the impact of mannan based prebiotics on growth and respiration of E. coli was assessed by observing microbial growth, oxygen consumption rate and extracellular acidification rate in the presence and absence of tetracycline. The findings further demonstrate the capabilities of MRF with respect to improving microbial antibiotic sensitivity, particularly in resistant strains. This potentially enables a more efficient control of resistant pathogens with food safety implications and promotion of more sustainable use of antibiotics in animal production systems.

Yeast Mannan-Rich Fraction Modulates Endogenous Reactive Oxygen Species Generation and Antibiotic Sensitivity in Resistant E. coli

Mannan-rich fraction (MRF) isolated from Saccharomyces cerevisiae has been studied for its beneficial impact on animal intestinal health. Herein, we examined how MRF affected the formation of reactive oxygen species (ROS), impacting antibiotic susceptibility in resistant Escherichia coli through the modulation of bacterial metabolism. The role of MRF in effecting proteomic change was examined using a proteomics-based approach. The results showed that MRF, when combined with bactericidal antibiotic treatment, increased ROS production in resistant E. coli by 59.29 ± 4.03% compared to the control (p ≤ 0.05). We further examined the effect of MRF alone and in combination with antibiotic treatment on E. coli growth and explored how MRF potentiates bacterial susceptibility to antibiotics via proteomic changes in key metabolic pathways. Herein we demonstrated that MRF supplementation in the growth media of ampicillin-resistant E. coli had a significant impact on the normal translational control of the central metabolic pathways, including those involved in the glycolysis-TCA cycle (p ≤ 0.05).

Effect of Mannan-rich fraction supplementation on commercial broiler intestinum tenue and cecum microbiota

BACKGROUND

The broiler gastrointestinal microbiome is a potent flock performance modulator yet may also serve as a reservoir for pathogen entry into the food chain. The goal of this project was to characterise the effect of mannan rich fraction (MRF) supplementation on microbiome diversity and composition of the intestinum tenue and cecum of commercial broilers. This study also aimed to address some of the intrinsic biases that exist in microbiome studies which arise due to the extensive disparity in 16S rRNA gene copy numbers between bacterial species and due to large intersample variation.

RESULTS

We observed a divergent yet rich microbiome structure between different anatomical sites and observed the explicit effect MRF supplementation had on community structure, diversity, and pathogen modulation. Birds supplemented with MRF displayed significantly higher species richness in the cecum and significantly different bacterial community composition in each gastrointestinal (GI) tract section. Supplemented birds had lower levels of the zoonotic pathogens Escherichia coli and Clostridioides difficile across all three intestinum tenue sites highlighting the potential of MRF supplementation in maintaining food chain integrity. Higher levels of probiotic genera (eg. Lactobacillus and Blautia) were also noted in the MRF supplemented birds. Following MRF supplementation, the cecum displayed higher relative abundances of both short chain fatty acid (SFCA) synthesising bacteria and SCFA concentrations.

CONCLUSIONS

Mannan rich fraction addition has been observed to reduce the bioburden of pathogens in broilers and to promote greater intestinal tract microbial biodiversity. This study is the first, to our knowledge, to investigate the effect of mannan-rich fraction supplementation on the microbiome associated with different GI tract anatomical geographies. In addition to this novelty, this study also exploited machine learning and biostatistical techniques to correct the intrinsic biases associated with microbiome community studies to enable a more robust understanding of community structure.

Effects of Protein-Chelated Zinc Combined with Mannan-Rich Fraction to Replace High-Dose Zinc Oxide on Growth Performance, Nutrient Digestibility, and Intestinal Health in Weaned Piglets

A total of 168 weaned piglets (average initial body weight of 7.70 ± 0.75 kg) were used in a 4-week feeding trial to investigate the effects of dietary supplementation with protein-chelated zinc (Zn-Pro) alone or combined with a mannan-rich fraction (MRF) to replace high-dose zinc oxide (ZnO) for weaned piglets. The dietary treatments included a basal diet as control (CON), a ZnO diet (basal diet + 1600 mg Zn/kg from ZnO), a Zn-Pro diet (basal diet + 60 mg Zn/kg from Zn-Pro), and a MRF plus Zn-Pro diet (MRP, basal diet + 800 mg/kg MRF + 60 mg Zn/kg from Zn-Pro). The average daily gain of piglets in the MRP group was higher (p ≤ 0.05) than that in CON and Zn-Pro groups during d 15-28 and d 1-28 of experiment. The apparent total tract digestibility of dry matter, organic matter, and crude protein in the MRP group was higher (p ≤ 0.05) than that in the CON group. The serum insulin-like growth factor-1 level in the MRP group was markedly higher (p ≤ 0.05) than that of piglets in the other three treatment groups. Piglets fed the Zn-Pro and ZnO diets had greater (p ≤ 0.05) acetic acid in cecal digesta than those fed the CON diet, while the MRP diet had higher (p ≤ 0.05) cecal propionate concentration than those that were fed the CON diet on d 28 of experiment. Moreover, the villus height of ileum in the MRP group tended to be greater than the CON group (p = 0.09). Compared with the CON and MRP groups, the relative abundance of Lactobacillaceae (p = 0.08) and Lachnospiraceae (p = 0.09) in the Zn-Pro group showed an increasing trend. The relative abundance of Prevotellaceae in the Zn-Pro group was significantly lower (p ≤ 0.05) than that in the MRP group. In conclusion, the combined addition of MRF and Zn-Pro acted as a suitable alternative to ZnO to beneficially support the growth performance and intestinal health of weaned piglets, as well as contribute to a lower diarrhea rate and environmental pollution from fecal zinc excretion.

Comparative Analysis of Mannans Extraction Processes from Spent Yeast Saccharomyces cerevisiae

Mannans are outstanding polysaccharides that have gained exponential interest over the years. These polysaccharides may be extracted from the cell wall of Saccharomyces cerevisiae, and recovered from the brewing or synthetic biology industries, among others. In this work, several extraction processes-physical, chemical and enzymatic-were studied, all aiming to obtain mannans from spent yeast S. cerevisiae. Their performance was evaluated in terms of yield, mannose content and cost. The resultant extracts were characterized in terms of their structure (FT-IR, PXRD and SEM), physicochemical properties (color, molecular weight distribution, sugars, protein, ash and water content) and thermal stability (DSC). The biological properties were assessed through the screening of prebiotic activity in Lactobacillus plantarum and Bifidobacterium animalis. The highest yield (58.82%) was achieved by using an alkaline thermal process, though the correspondent mannose content was low. The extract obtained by autolysis followed by a hydrothermal step resulted in the highest mannose content (59.19%). On the other hand, the extract obtained through the enzymatic hydrolysis displayed the highest prebiotic activity. This comparative study is expected to lay the scientific foundation for the obtention of well-characterized mannans from yeast, which will pave the way for their application in various fields.

Dietary mannan oligosaccharides strengthens intestinal immune barrier function via multipath cooperation during Aeromonas Hydrophila infection in grass carp (Ctenopharyngodon Idella)

In recent years, mannose oligosaccharide (MOS) as a functional additive is widely used in aquaculture, to enhance fish immunity. An evaluation of the effect of dietary MOS supplementation on the immune barrier function and related signaling molecules mechanism of grass carp (Ctenopharyngodon idella) was undertaken in the present study. Six diets with graded amounts of MOS supplementation (0, 200, 400, 600, 800, and 1000 mg/kg) were fed to 540 grass carp over 60 days. To examine the immune response and potential mechanisms of MOS supplementation on the intestine, a challenge test was conducted using injections of Aeromonas hydrophila for 14 days. Results of the study on the optimal supplementation with MOS were found as follows (1) MOS enhances immunity partly related to increasing antibacterial substances content and antimicrobial peptides expression; (2) MOS attenuates inflammatory response partly related to regulating the dynamic balance of intestinal inflammatory cytokines; (3) MOS regulates immune barrier function may partly be related to modulating TLRs/MyD88/NFκB and TOR/S6K1/4EBP signalling pathways. Finally, the current study concluded that MOS supplementation could improve fish intestinal immune barrier function under Aeromonas hydrophila infected conditions.

Invited review: strategic adoption of antibiotic-free pork production: the importance of a holistic approach

The discovery of the use of antibiotics to enhance growth in the 1950s proved to be one of the most dramatic and influential in the history of animal agriculture. Antibiotics have served animal agriculture, as well as human and animal medicine, well for more than seven decades, but emerging from this tremendous success has been the phenomenon of antimicrobial resistance. Consequently, human medicine and animal agriculture are being called upon, through legislation and/or marketplace demands, to reduce or eliminate antibiotics as growth promotants and even as therapeutics. As explained in this review, adoption of antibiotic-free (ABF) pork production would represent a sea change. By identifying key areas requiring attention, the clear message of this review is that success with ABF production, also referred to as "no antibiotics ever," demands a multifaceted and multidisciplinary approach. Too frequently, the topic has been approached in a piecemeal fashion by considering only one aspect of production, such as the use of certain feed additives or the adjustment in health management. Based on the literature and on practical experience, a more holistic approach is essential. It will require the modification of diet formulations to not only provide essential nutrients and energy, but to also maximize the effectiveness of normal immunological and physiological capabilities that support good health. It must also include the selection of effective non-antibiotic feed additives along with functional ingredients that have been shown to improve the utility and architecture of the gastrointestinal tract, to improve the microbiome, and to support the immune system. This holistic approach will require refining animal management strategies, including selection for more robust genetics, greater focus on care during the particularly sensitive perinatal and post-weaning periods, and practices that minimize social and environmental stressors. A clear strategy is needed to reduce pathogen load in the barn, such as greater emphasis on hygiene and biosecurity, adoption of a strategic vaccine program and the universal adoption of all-in-all-out housing. Of course, overall health management of the herd, as well as the details of animal flows, cannot be ignored. These management areas will support the basic biology of the pig in avoiding or, where necessary, overcoming pathogen challenges without the need for antibiotics, or at least with reduced usage.

Yeast-Derived Products: The Role of Hydrolyzed Yeast and Yeast Culture in Poultry Nutrition—A Review

Simple Summary

Yeast and yeast-derived products are largely employed in animal nutrition to support animals’ health and to improve their performance. Thanks to their components, including mannans, β-glucans, nucleotides, vitamins, and other compounds, yeasts have numerous beneficial effects. Among yeast-derived products, hydrolyzed yeasts and yeast cultures have received less attention, but, although the results are somewhat conflicting, in most of the cases, the available literature shows improved performance and health in poultry. Thus, the aim of this review is to provide an overview of hydrolyzed-yeast and yeast-culture employment in poultry nutrition, exploring their effects on the production performance, immune response, oxidative status, gut health, and nutrient digestibility. A brief description of the main yeast bioactive compounds is also provided.

Abstract

Yeasts are single-cell eukaryotic microorganisms that are largely employed in animal nutrition for their beneficial effects, which are owed to their cellular components and bioactive compounds, among which are mannans, β-glucans, nucleotides, mannan oligosaccharides, and others. While the employment of live yeast cells as probiotics in poultry nutrition has already been largely reviewed, less information is available on yeast-derived products, such as hydrolyzed yeast (HY) and yeast culture (YC). The aim of this review is to provide the reader with an overview of the available body of literature on HY and YC and their effects on poultry. A brief description of the main components of the yeast cell that is considered to be responsible for the beneficial effects on animals’ health is also provided. HY and YC appear to have beneficial effects on the poultry growth and production performance, as well as on the immune response and gut health. Most of the beneficial effects of HY and YC have been attributed to their ability to modulate the gut microbiota, stimulating the growth of beneficial bacteria and reducing pathogen colonization. However, there are still many areas to be investigated to better understand and disentangle the effects and mechanisms of action of HY and YC.

An Antioxidant Supplement Function Exploration: Rescue of Intestinal Structure Injury by Mannan Oligosaccharides after Aeromonas hydrophila Infection in Grass Carp (Ctenopharyngodon idella)

Mannan oligosaccharides (MOS) are a type of functional oligosaccharide which have received increased attention because of their beneficial effects on fish intestinal health. However, intestinal structural integrity is a necessary prerequisite for intestinal health. This study focused on exploring the protective effects of dietary MOS supplementation on the grass carp’s (Ctenopharyngodon idella) intestinal structural integrity (including tight junction (TJ) and adherent junction (AJ)) and its related signalling molecule mechanism. A total of 540 grass carp (215.85 ± 0.30 g) were fed six diets containing graded levels of dietary MOS supplementation (0, 200, 400, 600, 800 and 1000 mg/kg) for 60 days. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila for 14 days. We used ELISA, spectrophotometry, transmission electron microscope, immunohistochemistry, qRT-PCR and Western blotting to determine the effect of dietary MOS supplementation on intestinal structural integrity and antioxidant capacity. The results revealed that dietary MOS supplementation protected the microvillus of the intestine; reduced serum diamine oxidase and d-lactate levels (p < 0.05); enhanced intestinal total antioxidant capacity (p < 0.01); up-regulated most intestinal TJ and AJ mRNA levels; and decreased GTP-RhoA protein levels (p < 0.01). In addition, we also found several interesting results suggesting that MOS supplementation has no effects on ZO-2 and Claudin-15b. Overall, these findings suggested that dietary MOS supplementation could protect intestinal ultrastructure, reduce intestinal mucosal permeability and maintain intestinal structural integrity via inhibiting MLCK and RhoA/ROCK signalling pathways.

Performance and environmental impact of egg production in response to dietary supplementation of mannan oligosaccharide in laying hens: a meta-analysis

A meta-analysis was conducted to examine the effect of supplementing mannan oligosaccharide (MOS; Bio-Mos, Alltech Inc., Nicholasville, KY) in the diets of laying hens on the performance and environmental impact of egg production. Data on production performance (feed intake, hen-day production [HDP], feed conversion ratio [FCR], and mortality) and egg quality attributes (egg weight, egg mass, and eggshell thickness) were extracted from 18 studies to build a database of comparisons between nonsupplemented diets (control) and diets supplemented with MOS. A total of 4,664 laying hens were involved in the comparisons and the average MOS dosage and age of hens were 0.97 kg/ton and 44 wk, respectively. The dataset was analyzed using the random-effects model to estimate the effect size of MOS supplementation on production performance and egg quality attributes. The impact of feeding MOS on the carbon footprint (feed and total emission intensities) of egg production was evaluated by using the meta-analysis results of production performance to develop a scenario simulation that was analyzed by a life cycle assessment (LCA) model. Overall pooled effect size (raw mean difference) indicated that MOS supplementation did not affect feed intake. In contrast, HDP increased by +1.76% and, FCR and mortality reduced by -26.64 g feed/kg egg and -2.39%, respectively. Dietary MOS did not influence egg weight while egg mass increased (P < 0.01) by +0.95 g/day/hen and eggshell thickness tended to increase (P = 0.07) by +0.05 mm. Subgroup analysis indicated that dietary MOS exhibited consistent improvement on HDP and FCR under several study factors (age of hens, number of hens, production challenges, MOS dosage, and study duration). Additionally, the simulated LCA revealed that supplementing MOS decreased feed and total emission intensities of egg production by -1.3 and -1.5%, respectively. Overall, dietary supplementation of MOS at 1.0 kg/ton improved the production performance of laying hens and reduced the carbon footprint and, therefore, can enhance the sustainability credentials of egg production.

Supplementing Mannan Oligosaccharide Reduces the Passive Transfer of Immunoglobulin G and Improves Antioxidative Capacity, Immunity, and Intestinal Microbiota in Neonatal Goats

Successful establishment of passive immunity (PIT) and regulation of intestinal microbiota are crucial for ruminants to maintain body health and reduce the risk of disease during the neonatal period. Thus, the objective of this study was to investigate the effects of mannan oligosaccharide (MOS) supplementation on passive transfer of immunoglobulin G (IgG), serum inflammatory cytokines and antioxidant levels as well as bacteria composition in the ileal digesta. A total of 14 healthy neonatal Ganxi black goats with similar birth weight (BW: 2.35 ± 0.55 kg) were selected and allocated into two groups, only fed colostrum and milk replacer (CON, n = 7) and supplemented MOS (0.06% of birth BW) in the colostrum and milk replacer (MOS, n = 7). The results indicated that MOS supplementation significantly reduced (p < 0.05) serum IgG level at 3 and 6 h after colostrum feeding. Serum GLP-1 level of goats in the MOS group was significantly lower (p = 0.001) than that in the CON group. Goats in the MOS group had higher serum CAT and lower MDA level than those in the CON group (p < 0.05). Serum anti-inflammatory cytokine level of interleukin 4 (IL-4) was increased (p < 0.05), while pro-inflammatory cytokine IL-6 level was reduced (p < 0.05) in the MOS group when compared with the CON group. In addition, MOS supplementation remarkably increased (p < 0.05) the level of secretory IgA (sIgA) in the ileal digesta. Principal coordinate analysis of 16S rRNA sequence based on Brinary jaccard, Bray curtis, and weighted UniFrac distance of ileal microbiota showed a distinct microbial differentiation between the CON and MOS groups (p < 0.05). The relative abundance of Firmicutes in the MOS group was higher than that in the CON group, while the abundance of Verrucomicrobia was lower in the MOS group than that in the CON group at the phylum level (p < 0.05). The relative abundance of Proteobacteria tended to decrease (p = 0.078) in the MOS group at the phylum level. The results of LEfSe analysis showed that MOS group was characterized by a higher relative abundance of Lactobacillus, while the CON group was represented by a higher relative abundance of Akkermansia and Ruminiclostridium_5. Our findings demonstrated that MOS supplementation during the neonatal period increases antioxidant capacity and reduces the inflammatory response, and promotes IgA secretion and Lactobacillus colonization in the ileum. Thus, MOS induced positive effects are more pronounced in neonatal goats that might be an effective approach to maintain intestinal health and improve the surviving rate of neonatal ruminants.

Maternal Nutrition During Late Gestation and Lactation: Association With Immunity and the Inflammatory Response in the Offspring

The immature immune system at birth and environmental stress increase the risk of infection in nursing pigs. Severe infection subsequently induces intestinal and respiratory diseases and even cause death of pigs. The nutritional and physiological conditions of sows directly affect the growth, development and disease resistance of the fetus and newborn. Many studies have shown that providing sows with nutrients such as functional oligosaccharides, oils, antioxidants, and trace elements could regulate immunity and the inflammatory response of piglets. Here, we reviewed the positive effects of certain nutrients on milk quality, immunoglobulin inflammatory response, oxidative stress, and intestinal microflora of sows, and further discuss the effects of these nutrients on immunity and the inflammatory response in the offspring.

Effects of Dietary Mannan Oligosaccharides on Non-Specific Immunity, Intestinal Health, and Antibiotic Resistance Genes in Pacific White Shrimp Litopenaeus vannamei

This study was conducted to comprehensively investigate the beneficial effects of a mannan oligosaccharide product (hereinafter called MOS) on Litopenaeus vannamei and optimum level of MOS. Five isonitrogenous and isolipid diets were formulated by adding 0%, 0.02%, 0.04%, 0.08%, and 0.16% MOS in the basal diet. Each diet was randomly fed to one group with four replicates of shrimp in an 8-week feeding trial. The results showed that dietary MOS improved the growth performance and the ability of digestion of shrimp. Dietary MOS significantly increased the activity of total superoxide dismutase, catalase, and glutathione peroxidase and decreased the content of malondialdehyde in plasma of shrimp. Dietary MOS significantly increased the activity of alkaline phosphatase and lysozyme in plasma and the hemocyte counts. Dietary MOS significantly upregulated the expression of Toll, lysozyme, anti-lipopolysaccharide factor, Crustin, and heat shock protein 70 in the hepatopancreas. And dietary MOS significantly upregulated the expression of intestinal mucin-2, mucin-5B, and mucin-19, while it decreased the expression of intestinal mucin-1 and macrophage migration inhibitory factor. Dietary MOS improved the bacterial diversity; increased the abundance of Lactobacillus, Bifidobacterium, Blautia, and Pseudoalteromonas; and decreased the abundance of Vibrio in the intestine. Shrimp fed MOS diets showed lower mortality after being challenged by Vibrio parahaemolyticus. Notably, this study found a decrease in antibiotic resistance genes and mobile genetic elements after MOS supplementation for the first time. The present results showed that diet with MOS supplementation enhanced the organismal antioxidant capacity and immunity, improved intestinal immunity, optimized intestinal microecology, mitigated the degree of antibiotic resistance, and increased the resistance to V. parahaemolyticus in L. vannamei, especially when supplemented at 0.08% and 0.16%.

Improving growth performance and blood profile by feeding autolyzed yeast to improve pork carcass and meat quality

The 63 commercial pigs were divided into three groups consisting of seven replicates of three piglets each. The experimental diets were (1) control diet, (2) diet with autolyzed yeast (AY) 0.5%, and (3) diet with AY 1.0%. Compared to the control group, using AY 0.5% in the diet reduced average daily feed intake (ADFI) and improved feed conversion ratio (FCR) (p < 0.05). The blood urea nitrogen (BUN) and neutrophil/lymphocyte ratio (N/L) in blood decreased with the addition of AY 0.5% (p < 0.05). The pH at 6-h postmortem of meat in the 0.5% AY diet group was higher than for the control group (p < 0.05). Backfat thickness (p = 0.09) and P2-backfat thickness (p = 0.07) tended to decrease, while the fat free index (FFI; p = 0.07) tended to increase with 0.5% AY supplementation. The protein percentage (p = 0.07) and the a* value (redness) (p = 0.08) in the meat tended to increase, and the springiness increased with 0.5% AY supplementation (p < 0.05). An appropriate level of AY supplementation can impact positively on the physiological functions in swine with a consequent seems to improve in qualitative traits of the meat quality.

Mannans and mannan oligosaccharides (MOS) from Saccharomyces cerevisiae - A sustainable source of functional ingredients

Sustainable industry practices and circular economy concepts encourage the transformation of production waste into by-products. Saccharomyces cerevisiae is widely used in fermentation industry worldwide, generating large amounts of spent yeast which is mainly directed to animal feed or discarded as waste. Instead of becoming and environmental problem, spent yeast can be directed to the extraction of valuable compounds such as mannans and mannan oligosaccharides (MOS). This review presents a compilation of the studies up to date regarding the different chemical, enzymatic, mechanical or physical processes addressed for mannans extraction and MOS production. Additionally, the existing studies on the chemical modification of mannans aimed to improve specific characteristics are also discussed. Finally, the more relevant bioactivities and potential applications of mannans, MOS and mannose are presented, together with products on the market containing these compounds.

Effect of a Polyphenol-Based Additive in Pig Diets in the Early Stages of Growth

The weaning period is a stressful period for the gastrointestinal tract (GIT) of piglets. This work aims to evaluate the effects of the commercial polyphenol-based product GreenFIS^® on: (1) GIT health and performance of 60 weaned piglets; (2) digestibility in 18 growing pigs. Three diets were tested: a control diet (C), C plus 2.5 g of GreenFIS^®/kg C (T1), and C plus 5 g of GreenFIS^®/kg C (T2). After the post-weaning trial three piglets per treatment were sacrificed for the GIT histological analysis. No differences between diets were recorded in terms of growing performance or clinical and biochemical blood parameters. The GIT histological analysis did not show any indicators of inflammation for any of the groups. The feces of the two extreme treatments (C and T2) were analyzed for microbiota, revealing a greater presence of the Ruminococcus bromii group, positively associated with starch degradation, in T2. In the second experiment six pigs per treatment were randomly chosen for the digestibility study. The inclusion of GreenFIS^® at both levels led to a higher fecal digestibility of gross energy (86.2%, 89.1%, and 89.5%, for C, T1, and T2, respectively) and crude protein (87.0%, 90.2%, and 90.0%). In conclusion, the additive did not improve, in the excellent experimental hygienic conditions, the gut health, but it did increase nutrient digestibility.

Antioxidant activity of yeast mannans and their growth-promoting effect on Lactobacillus strains

Yeast mannans from Saccharomyces cerevisiae (123.2 kDa, 40.5 kDa and 21.3 kDa) were prepared. The scavenging abilities of Fe²⁺, OH˙, and O₂˙^- and protective capacities against lipid peroxidation and oxidative DNA damage increased with the reduction of the molecular weights of yeast mannans. The highest scavenging abilities of Fe²⁺, OH˙ and O₂˙^- (25.32%, 70.8%, and 61.5%) were observed with YM-90, and it showed an anti-lipid peroxidation capacity of 65.82%, which was much stronger than that of vitamin C (VC), with a thiobarbituric acid-reactive substance (TBARS) inhibition rate of 80.41%. However, the highest DPPH scavenging rate (88.7%) was exhibited by YM-30. In addition, the growth-promoting effect of yeast mannans on Lactobacillus strains was further confirmed, and a 54.2% increment of Lactobacillus plantarum ZWR5 cell viability was achieved by YM-90. The results indicated the potential industrial applications of this yeast mannan technology in therapeutic and nutraceutical production.

Effect of yeast cell wall supplementation on intestinal integrity, digestive enzyme activity and immune traits of broilers

1. The protective layer formed by intestinal epithelial cells acts as a barrier preventing the adhesion of pathogenic bacteria, aids digestion and passage of nutrients and reduces damage caused from toxins on the gastrointestinal tract. This study was conducted to investigate the effects of a yeast cell wall-based product (YCW), on broiler intestinal integrity, digestive enzyme capacity and immune function.2. A 35-d trial involving 246, one-d-of-hatch male broiler chickens was carried out at a trial facility at Agri-Food Biosciences Institute (AFBI, Belfast, UK). Birds were randomly allocated into 6 pens at day of hatch (41 birds/pen; 123 birds/group). Pens were divided into two groups: (1) basal diet and (2) basal diet that incorporated YCW at the manufacturers' recommended inclusion levels (Alltech Inc., Lexington, Kentucky, USA).3. In this study, YCW supplementation affected broiler intestinal morphology resulting in greater crypt depth, villus height and surface area, goblet cell density and mucus layer thickness and lower muscularis mucosae thickness. The digestive enzymes, maltase, sucrase and alkaline phosphatase, were significantly higher in the YCW supplemented group compared to the control. The expression levels of pro-inflammatory cytokines, IL-1β, IL-12 and IL-18, were significantly lower as was necroptotic cell death in YCW supplemented birds.4. In conclusion, under the conditions of this study, YCW supplementation positively affected intestinal health parameters in broilers following 35-d supplementation.

Effect of non-encapsulated and encapsulated active dried yeast on blood cell count, blood metabolites, and immune response of finishing beef heifers

A study was conducted to evaluate whether encapsulated active dried yeast (EDY), compared with non-protected active dried yeast (ADY) or antibiotics (ANT), improved immune response and blood metabolites of finishing beef heifers. Blood urea nitrogen was lower (P < 0.05) with supplemented ADY and mixture of ADY and EDY (MDY) compared with control. Supplementation of MDY also resulted in lower (P < 0.05) red blood cell distribution width than control. Lipopolysaccharide-binding protein was less (P < 0.05) for EDY than control, ANT, and ADY as well as cytokine concentration of interleukin-6 was less (P < 0.05) for MDY versus control.

Effects of a blend of mannan and glucan on growth performance, apparent nutrient digestibility, energy status, and whole-blood immune gene expression of beef steers during a 42-d receiving period

We examined the effects of dietary supplementation of a blend of mannan and glucan on the growth performance, energy status, and whole-blood immune gene expression of newly weaned beef steers during a 42-d receiving period. Forty-eight newly weaned Angus crossbred steers (2-d post-weaning; 199 ± 13 kg of initial body weight [BW]) from a single source were stratified by BW and randomly assigned to one of the two treatments: basal diet with no additive (CON; n = 24) or a basal diet top-dressed with 5 g of a blend of mannan and glucan (MANGLU; n = 24). Average daily gain (ADG) and feed efficiency (FE) from days 1 to 14, 15 to 42, and 1 to 42 were calculated from daily dry matter intake (DMI) and weekly BW. Blood samples were collected on days 0, 14, and 42 for measurement of plasma glucose and nonesterified fatty acids (NEFA). Blood samples collected on days 14 and 42 were composited for each steer for untargeted carbonyl-metabolome analysis (measurement of carbonyl-containing metabolites). Expression of 84 immune-related genes was analyzed on blood samples collected on day 42. Beginning on days 37 to 42, total mixed ration, refusals, and fecal samples were collected once daily to determine apparent total tract digestibility of DM, CP, NDF, and ADF using indigestible NDF as an internal marker. Over the 42-d feeding trial, supplemental MANGLU tended to increase final BW (P = 0.07) and ADG (P = 0.06). Compared to CON, beef steers fed supplemental MANGLU had greater (P = 0.01) DMI during the first 14 d, greater DM digestibility (P = 0.03), and tended to have greater NDF digestibility (P = 0.09). No treatment effects (P > 0.10) on plasma glucose and NEFA on days 14 and 42 were detected; however, carbonyl-metabolome analysis revealed increased (FDR ≤ 0.05) plasma concentrations of galactose and glyceraldehydes, and altered (FDR ≤ 0.05) concentrations of some microbiome-derived metabolites in beef steers fed MANGLU. Compared with CON, MANGLU increased (P ≤ 0.05) the expression of five immune-related genes involved in recognition of and mounting immune defense against microbial pathogens. In conclusion, the results of this study demonstrated that supplemental MANGLU enhances beef cattle immunocompetence and productivity during feedlot receiving period.

Antinociceptive and anti-inflammatory activity of α-d-mannan from Pseudozyma sp

Pseudozyma sp. are yeasts that are commercially important due to their production of glycolipid biosurfactants, squalene, itaconic acid, and exopolysaccharide. The search for other analgesia inducing drugs, such as opiates and non-steroidal anti-inflammatory drugs (NSAIDs), as alternatives is beneficial. In this study, the antinociceptive and anti-inflammatory actions of α-d-mannan were studied using acetic acid-induced writhing, open field test, formalin test, and carrageenan-induced paw oedema tests in mice. The α-d-mannan obtained from Pseudozyma sp. was confirmed by methylation analysis, 1D and 2D NMR spectroscopic analysis, and GC-MS. The results show that α-d-mannan from Pseudozyma sp. has analgesic and anti-inflammatory activities.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-020-02635-1.

Effect of Supplementation of Fermented Yeast Culture on Hormones and Their Receptors on Exposure to Higher Temperature and on Production Performance after Exposure in Nicobari Chickens

Heat stress (HS) affects the production performance in chickens and causes economic loss to the producers. Most of the studies have been conducted on and for the welfare of broilers. We still lack information on the physiological parameters being affected during chronic heat stress in layers. To fill this gap, the present study evaluated the effect of heat stress (induced in the chamber) during the prelaying period (21-23 weeks) on plasma levels of the hormones leptin and ghrelin and GH and expression of the respective receptors and heat stress markers. Three groups were considered, one at room temperature (CR) and the other two groups (SH and CH) subjected to heat stress at 39°C for four hours for three weeks (21-23 weeks of age). The SH group (SH) feed was supplemented with fermented yeast culture (FYC, 700 mg/kg), whereas the CH group was devoid of it. After that, all the groups were shifted to shed under natural ambient conditions till 31 weeks of age. Studies were restricted to production performance only. Feed offered without yeast culture (CH group) had a smaller concentration of plasma hormones (P < 0.01) and increased expression fold of the hormone receptors (P < 0.01). Further, the group also presented higher liver AMP kinase enzyme, plasma MDA (malondialdehyde), and cholesterol concentrations. These changes likely explained the decrease in feed intake and the CH group's body weight and further reduced the production performance during the laying period. Supplementation with FYC to birds had an opposite effect on the above-mentioned parameters, reducing HS effects. In summary, supplementation with FYC (700 mg/kg) maintained physiological parameters as in the CR group under HS conditions and negated adverse effects on parameters both before and during laying periods.

Digestible and metabolizable energy concentrations and amino acid digestibility of dried yeast and soybean meal for growing pigs

Energy values and amino acid (AA) digestibility of dried yeast (DY) and soybean meal (SBM) were determined in 2 experiments with growing pigs. Experiment 1 was conducted to determine the digestible energy (DE) and metabolizable energy (ME) in DY and SBM. Thirty barrows with a mean initial body weight (BW) of 20.6 kg (SD = 1.04) were assigned to 5 dietary treatments in a randomized complete block design with period and BW as blocking factors. A reference diet was prepared with corn, canola meal, and soybean oil as energy-contributing ingredients. Four additional diets were prepared by adding 5% and 10% DY or SBM at the expense of energy-contributing ingredients in the reference diet. The ratio of corn, canola meal, and soybean oil was kept consistent across the experimental diets. Each experimental period consisted of 5-d adaptation and 5-d quantitative collection of feces and urine. Test ingredient-associated DE or ME intake (kcal/d) was regressed against test ingredient intake [kg dry matter (DM)/d] to estimate the DE or ME in test ingredients as the slope of linear regression model. The DE in DY was estimated at 3,933 kcal/kg DM, which was not different from the estimated DE in SBM at 4,020 kcal/kg DM. Similarly, there was no difference between DY and SBM in the estimated ME (3,431 and 3,756 kcal/kg DM, respectively). Experiment 2 was conducted to determine the standardized ileal digestibility (SID) of AA in DY and SBM. Twenty-one barrows with a mean initial BW of 20.0 kg (SD = 1.31) were surgically fitted with T-cannulas at the distal ileum and assigned to 3 dietary treatments in a randomized complete block design with BW as a blocking factor. Two semi-purified diets containing DY or SBM as the sole nitrogen source and one nitrogen-free diet (NFD) were prepared. The NFD was used to estimate the basal ileal endogenous losses of CP and AA. Pigs were fed the 3 diets for 5 d as adaptation, followed by 2 d of feeding with ileal digesta collection. The SID of AA, except Gly and Pro, in DY was less (P < 0.05) than in SBM. The SID of indispensable AA in DY ranged from 64.1% for Thr to 85.2% for Arg, and those in SBM ranged from 83.9% for Thr to 91.8% for Arg. In conclusion, energy values of DY are not different from those of SBM, whereas AA in DY is less digestible than in SBM. The estimated DE and ME as well as the SID of AA in DY and SBM can be used in diet formulation for growing pigs using these ingredients.

Biosynthesis of low-molecular-weight mannan using metabolically engineered Bacillus subtilis 168

Mannans are functional polysaccharides with unique biological activities that have been employed widely in food, medicine and pharmaceutics. Recent breakthroughs in plant polysaccharide metabolism identified numerous genes involved in the biosynthesis of mannans. However, constructing highly efficient low-cost microbial cell factories to produce low-molecular-weight (LMW) mannans remains challenging. In this work, we designed a de novo mannan synthetic pathway in food-grade Bacillus subtilis, resulting in mannan accumulation of 0.97 g/L. By co-expressing the identified committed genes (manC, manB, manA and pgi), mannan production was significantly increased to 2.5 g/L. Furthermore, by redirecting the carbon flux using a glucose-repressed promoter to control pfkA expression, mannan production was substantially increased to 4.1 g/L. Production was further enhanced to 12.6 g/L (average MW 6370 Da) in 3-L fed-batch fermentation. This work provides alternative synthetic pathways for metabolic engineering of LMW mannans in B. subtilis, and a useful, optimisable approach to enhance mannans production.

Yeast cell wall mannan rich fraction modulates bacterial cellular respiration potentiating antibiotic efficacy

Now more than ever there is a demand to understand the mechanisms surrounding antibiotic resistance and look for alternative ways to impact phenotypic antibiotic outcome. Cellular energetics can be impacted by many bacteriostatic and bactericidal antibiotics, which affect metabolism and energy output, resulting in a reduction of cell growth or induction of cell death respectively. In this study, we provide evidence that a mannan rich fraction (MRF) from the cell wall of Saccharomyces cerevisiae modulates growth of antibiotic susceptible and resistant Escherichia coli and potentiates bactericidal antibiotic efficiency through modulation of bacterial cellular respiration. The role of MRF in modulating bactericidal impact and cellular metabolic state were assessed in E. coli by monitoring microbial growth and by measuring oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) using the Seahorse XFe96 Analyser, respectively. This work further illustrates the link between bacterial susceptibility to antibiotics (phenotypic resistance) and resistance through modulation of bacterial metabolism. This is the first example of yeast MRF enabling collateral sensitivity to antibiotics in vitro and supports the search for alternative strategies to promote animal health without contributing to the growing issue of antimicrobial resistance.

Yeast-Derived Formulations Are Differentially Fermented by the Canine and Feline Microbiome As Assessed in a Novel In Vitro Colonic Fermentation Model

The current study evaluated the effect of five yeast-derived formulations (T1-T5) on microbial metabolism and composition of the canine and feline gut microbiota using a novel in vitro colonic incubation approach. This novel in vitro model allowed for growth of the entire spectrum of dog- and cat-derived bacteria from the inoculum, thus offering an excellent platform to evaluate effects of nutritional interventions on the gut microbiota. Further, yeast-derived ingredients differentially increased production of acetate, propionate, butyrate, ammonium, and branched short-chain fatty acids, with T5 and T1 consistently stimulating propionate and butyrate, respectively. 16S-targeted Illumina sequencing coupled with flow cytometry provided unprecedented high-resolution quantitative insights in canine and feline microbiota modulation by yeast-derived ingredients, revealing that effects on propionate production were related to Prevotellaceae, Tannerellaceae, Bacteroidaceae, and Veillonellaceae members, while effects on butyrate production were related to Erysipelotrichaceae, Lachnospiraceae, Ruminococcaceae, and Fusobacteriaceae. Overall, these findings strengthen the health-promoting potential of yeast-derived ingredients.

Yeast-rich mannan fractions in duck cultivation: prospects of using

Introduction. Due to the trend of avoiding antibiotics and acquiring eco-friendly products, the use of environmentally safe preparations is becoming increasingly relevant in poultry farming. Study objects and methods. We used Salmonella enteritidis and Campylobacter jejuni isolated from poultry carcasses. At the first in vitro stage, we studied the ability of mannan oligosaccharides, isolated from the cell walls of Saccharomyces cerevisiae yeast, to adsorb bacterial pathogens. At the second stage, we studied the influence of fraction on the activity, colonization and microflora composition of ducklings’ intestines. At the third stage, we determined the antagonistic activity of Bifidobacterium spp. (Bifidobacterium lactis, Bifidobacterium longum, Bifidobacterium bifidum) and Lactobacillus spp. (Lactobacillus fermentun, Lactobacillus salivarius, Lactobacillus acidophilus) against Salmonella enteritidis and Campylobacter jejuni isolates. The experiment was conducted on the ducklings of Star 53 H.Y. cross. Their diet was supplemented with probiotics, prebiotics, and their combination. Results and discussion. In vitro studies showed the ability of mannan oligosaccharides isolated from the cell walls of Saccharomyces cerevisiae yeast to adsorb Salmonella enteritidis and Campylobacter jejun. In vivo experiment showed the ability of mannan oligosaccharides to prevent colonization of poultry intestines by bacterial pathogens with type I fimbriae. Conclusion. The reisolation rate of ducks infected with Salmonella enteritidis was 53.6% lower, and those infected with Campylobacter jejuni, 66.2% lower than the control. Mannan oligosaccharides added to the diet did not affect the concentration of lactobacilli, enterococci, and anaerobic bacteria in the ducks’ intestines. A combined use of Bifidobacterium spp. and mannan oligosaccharides improved the preservation of poultry stock by 8.7%, which made it an effective way to prevent poultry salmonellosis.