Mannan rich fraction from yeast modulates inflammatory responses in intestinal cells (HT-29) exposed to Escherichia coli

Efficacy of Saccharomyces yeast postbiotics on cell turnover, immune responses, and oxidative stress in the jejunal mucosa of young pigs

This study aimed to determine the effects of Saccharomyces yeast postbiotics on cell turnover, immune responses, and oxidative stress in the jejunal mucosa of pigs. Thirty-two newly weaned pigs at 6.05 ± 0.24 kg were assigned to two dietary treatments based on a randomized complete block design. The treatments were control group receiving a basal diet and a group supplemented with Saccharomyces yeast postbiotics (175 g/ton diet) in the basal diet. After 35 d of the study, pigs were euthanized and jejunal mucosa were collected to assess immune status, oxidative stress, barrier markers, cell proliferation, and apoptosis. Saccharomyces yeast postbiotics reduced (P < 0.05) the fecal score from d 3 to d 7 and tended to increase the gene expression of interferon-γ (IFN-γ) (P = 0.071) and mammalian/mechanistic target of rapamycin (mTOR) (P = 0.080), decrease the gene expression of B-cell lymphoma 2-associated X protein 1 (BAX1) (P < 0.05), tended to decrease the gene expression of serum and glucocorticoid-induced protein kinase 1 (SGK1) (P = 0.066), increased (P < 0.05) cell proliferation in the crypts, and tended to increase the villus height (P = 0.078) and crypt depth (P = 0.052) in the jejunum. In conclusion, the supplementation of Saccharomyces yeast postbiotics in nursery diets reduced diarrhea within the first week after weaning and provided protection to the villi in the jejunum by enhancing the immune responses of nursery pigs, promoting crypt cell proliferation, and reducing the expression of genes associated with apoptosis without affecting inflammatory and oxidative stress status in the jejunum of the nursery pigs.

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.

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.

Animal-derived free hydrolysate in animal cell culture: Current research and application advances

Fetal bovine serum (FBS) plays a crucial role in the composition of animal cell culture medium. However, conventional serum-based medium face numerous challenges. The use of animal-derived free hydrolysate (ADFH) has garnered significant attention in research and applications as a viable alternative to FBS-containing medium in animal cell culture. This article provides a comprehensive overview of the effects, mechanisms of action, and applications of ADFH in animal cell culture. ADFH serves as an effective substitute for FBS-containing medium, enhancing various cellular processes, including cell proliferation, viability, protein synthesis, production, survival, and stability. Several mechanisms of action for ADFH have been elucidated through scientific investigations, such as nutrient provision, activation of signaling pathways, regulation of protein synthesis and folding, protection against oxidative damage and apoptosis, as well as cell cycle regulation. Researches and applications of ADFH represent a promising approach to overcoming the limitations of FBS-containing medium and advancing the field of animal cell culture. This review provides a theoretical foundation for promoting the development of sustainable and alternative hydrolysates, as well as the continued progress of animal cell culture.

Bioprotective potential of lactic acid bacteria and their metabolites against enterotoxigenic Escherichia coli

Escherichia coli is one of the main pathogens that impacts swine production. Given the need for methods for its control, the in vitro effect of lactic acid bacteria (LAB) and their metabolites against E. coli F4 was evaluated through cell culture and microbiological analysis. The strains Limosilactobacillus fermentum 5.2, Lactiplantibacillus plantarum 6.2, and L. plantarum 7.1 were selected. To evaluate the action of their metabolites, lyophilized cell-free supernatants (CFS) were used. The effect of CFS was evaluated in HT-29 intestinal lineage cells; in inhibiting the growth of the pathogen in agar; and in inhibiting the formation of biofilms. The bioprotective activity of LAB was evaluated via their potential for autoaggregation and coaggregation with E. coli. The CFS did not show cytotoxicity at lower concentrations, except for L. fermentum 5.2 CFS, which is responsible for cell proliferation at doses lower than 10 mg ml^-1. The CFS were also not able to inhibit the growth of E. coli F4 in agar; however, the CFS of L. plantarum 7.1 resulted in a significant decrease in biofilm formation at a dose of 40 mg ml^-1. Regarding LAB, their direct use showed great potential for autoaggregation and coaggregation in vitro, thus suggesting possible effectiveness in animal organisms, preventing E. coli fixation and proliferation. New in vitro tests are needed to evaluate lower doses of CFS to control biofilms and confirm the bioprotective potential of LAB, and in vivo tests to assess the effect of LAB and their metabolites interacting with animal physiology.

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 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.