Beer yeast - How to regulate the intestinal tract of livestock and poultry

      As a high-quality feed additive, beer yeast regulates the intestinal microbiota of livestock and poultry at multiple levels. Its core is to achieve intestinal microbiota balance through the interaction between its own components (such as cell wall polysaccharides, oligosaccharides, nutrients, etc.) and intestinal microbiota, intestinal epithelial cells, and immune system. The specific mechanisms can be summarized as follows:

1、 Competitive inhibition of harmful bacterial adhesion and colonization

      The cell wall components of beer yeast, especially oligosaccharides (MOS), are the key to exerting this effect.

      One of the pathogenic mechanisms of harmful bacteria in the intestine, such as Escherichia coli, Salmonella, Clostridium perfringens, etc., is that their surface pili (such as F18 pili) specifically bind to the mannose receptors on the surface of intestinal epithelial cells, thereby adhering and colonizing the intestine.

      The MOS structure in beer yeast is similar to the mannose receptor on the surface of intestinal epithelial cells, and can serve as a "molecular bait" to bind with harmful bacteria pili, competitively blocking the adhesion sites between harmful bacteria and intestinal epithelial cells, preventing them from colonizing and being excreted with feces.

      For example, in piglets, MOS can significantly reduce the number of pathogenic Escherichia coli in the intestine; In broiler chickens, the colonization rate of Salmonella can be reduced, thereby reducing the risk of gut microbiota disruption.

2、 Provide prebiotic substrates to promote the proliferation of beneficial bacteria

      Functional oligosaccharides (such as MOS and oligofructose precursors) and some indigestible carbohydrates in beer yeast can be used as prebiotics by beneficial bacteria in the gut, indirectly promoting their proliferation.

      Beneficial bacteria in the gut, such as lactic acid bacteria, bifidobacteria, and Roy's bacteria, cannot directly utilize complex carbohydrates in host feed, but can rapidly proliferate by breaking down oligosaccharides (such as MOS) in beer yeast through their own metabolic enzymes as an energy source.

      After the proliferation of beneficial bacteria, they will further inhibit harmful bacteria through nutritional competition (such as growth restriction of harmful bacteria due to lack of nutrition); At the same time, short chain fatty acids (SCFAs, such as acetic acid, propionic acid, and butyric acid) produced by beneficial bacteria metabolism can lower the pH value of the intestine (making the intestinal environment more acidic), while most harmful bacteria (such as Escherichia coli and Clostridium) are not acid tolerant and their growth and reproduction will be significantly inhibited.

      For example, adding beer yeast to broiler feed can increase the number of lactic acid bacteria in the intestine by 20% -30%, increase SCFA concentration, and lower intestinal pH by 0.3-0.5 units, effectively inhibiting the reproduction of Clostridium perfringens.

3、 Enhance intestinal barrier function and reduce the triggering factors of microbial dysbiosis

      Beer yeast can indirectly maintain the stability of gut microbiota by improving the physical and immune barriers of the intestine.

      Promoting the health of intestinal epithelial cells: Beer yeast is rich in amino acids (such as glutamine), vitamins (such as B vitamins), and minerals, which can provide nutrition for intestinal epithelial cells, promote their proliferation and repair, maintain the integrity of intestinal villus structure (such as increasing villus height and reducing crypt depth), and reduce the risk of bacterial translocation caused by intestinal epithelial damage.

      Enhance tight junction function: β - glucan in beer yeast can activate the signaling pathway of intestinal epithelial cells (such as TLR4/NF - κ B pathway), promote the expression of tight junction proteins (such as occludin and claudin-1), reduce intestinal permeability, prevent harmful bacteria and their toxins (such as endotoxins) from entering the bloodstream, and avoid systemic inflammation caused by "intestinal leakage" that interferes with intestinal flora.

      Stimulating mucus secretion: Beer yeast can promote the secretion of mucus (mainly composed of mucin) by intestinal epithelial goblet cells. The mucus layer is the "physical protective layer" of the intestine, which can provide a planting environment for beneficial bacteria and prevent harmful bacteria from directly contacting the intestinal epithelium, maintaining the "spatial balance" of bacterial colonization.

4、 Regulating intestinal immunity and indirectly shaping microbiota structure

      The active ingredients of beer yeast, such as β - glucan and MOS, can indirectly affect the composition of the microbiota by activating local intestinal immunity.

      There are receptors on the surface of intestinal mucosal immune cells (such as macrophages, dendritic cells, T cells) that recognize yeast components (such as TLR2, TLR4). When yeast components bind to these receptors, they stimulate immune cells to secrete cytokines (such as IL-10, TNF - α) and antibodies (such as sIgA).

      Among them, sIgA can specifically bind to harmful bacteria, inhibit their activity, and promote their clearance; And anti-inflammatory cytokines such as IL-10 can reduce excessive intestinal inflammation, avoiding the indiscriminate killing of beneficial bacteria by inflammation (excessive inflammation can disrupt the balance of the microbiota and even lead to a decrease in beneficial bacteria).

      For example, adding beer yeast to laying hens can increase intestinal sIgA content by 15% -25%, significantly reduce intestinal inflammation caused by Salmonella, and maintain the dominant position of lactic acid bacteria.

summarize

      The regulation of intestinal microbiota in livestock and poultry by beer yeast is the result of "multi-component synergistic and multi pathway effects": it competitively inhibits harmful bacterial adhesion through MOS, promotes beneficial bacterial proliferation through prebiotic effects, enhances intestinal barrier through nutritional and immune regulation, and ultimately achieves the transformation of intestinal microbiota from "imbalance" to "balance". This mechanism is universally applicable in common livestock and poultry such as pigs, chickens, and ducks, and is also the core reason for its widespread use as a green feed additive.