Seaweed extract

Seaweed extract is an important intestinal tool with multiple key functions.

The interaction among intestinal barrier, immune function and host microbiota is the foundation for animals to achieve growth and health. Intestinal damage is an important cause of reduced nutritional efficiency, systemic inflammation and homeostatic imbalance. Therefore, an important part of animal nutrition is to obtain the best benefits of intestinal barrier, immune function and host microbiota through diet. More and more research and commercial practices show that algal extracts can provide positive and effective support for intestinal health, immune regulation and probiotic effects on the microbiota.

Algal polysaccharides have complex structures and unique components, such as uronic acid, xylose and rhamnose. The diverse branched structure and sulfate groups in algal polysaccharides are the important basis for their rich biological activities.

Sulfated polysaccharides are characteristic of macroalgae. This poly-anionic structure increases the solubility of algal polysaccharides and makes them highly compatible with intestinal mucus. This poly-anionic structure is easily recognized by host and microbial cells, thereby supporting normal physiological and metabolic activities of host and microbial cells.

In addition to good biocompatibility, sulfated algal polysaccharides also have good processing properties that are not found in general natural substances, such as insensitivity to heat treatment and extrusion, and thus can play the expected beneficial role in formulated preparations. Moreover, algal polysaccharides can promote the adhesion between components, which is conducive to the formation and stability of feed pellets.

The in vitro experiments of E. coli challenge on algal extract showed that the algal extract significantly alleviated the decrease of TEER (a marker of intestinal permeability, transepithelial electrical resistance) caused by E. coli infection. TEER remained stable in the negative control experiment, but rapidly declined in the positive control experiment. In animal models that trigger intestinal inflammation, algal extract reduced the paracellular exudation of FITC-dextran (a biomarker of intestinal permeability). In vitro studies have also demonstrated that algal extract can up-regulate the expression of genes encoding transmembrane proteins and scaffold proteins, which are essential for the optimal function of tight junction complexes. Additionally, algal extract can up-regulate the expression of genes encoding major mucin proteins, and the increased secretion of these proteins can prevent the attachment and colonization of pathogens on the intestinal epithelium.

In the challenge experiments targeting necrotic enteritis in broiler chickens, it was observed that algal extract promoted the improvement of intestinal integrity by enhancing the gene expression of tight junction proteins (CLDN1, CLDN3, and ZO1) in the jejunum, as well as reducing intestinal lesion scores and improving feed conversion rate.

Further research indicates that seaweed extracts can regulate the activation of the host's innate defense and adaptive immune response, promoting the synthesis of related immune mediators. For instance, seaweed extracts can enhance the host's resistance to intestinal pathogenic bacteria by increasing mucosal defense components such as immunoglobulin A (IgA). Additionally, in a model of necrotic enteritis combined infection in broilers, broilers treated with seaweed extracts showed lower serum calprotectin concentrations. Serum calprotectin concentration is a biomarker of intestinal inflammation and significantly increases when the intestine is in an inflammatory state. Moreover, in the model of necrotic enteritis combined infection in broilers, the use of seaweed extracts can upregulate the secretion levels of IL1β, IL12B, and IL10 in broilers, indicating an improvement in cell-mediated immune responses.