ISSUE FOCUS FEED & ADDITIVE MAGAZINE March 2024 31 are known antigens or in more difficult terms pathogen-associated-microbial-patterns (PAMP). PAMP are parts of bacteria that are recognized by receptors on immune cells and epithelial cells, which generates an immune response. More specifically, LPS is a ligand for Toll-like receptor 4 by its lipid domain. This receptor is mainly found on membranes of antigen presenting cells, for example monocytes, macrophages, and dendritic cells. The role of these immune cells is to initiate an innate immune response and activate different lymphocytes. After binding of LPS to these immune cells, a cascading event triggers production of pro-inflammatory cytokines and mediation of an inflammatory response. Prolonged and chronic exposure eventually leads to gut inflammation, intestinal damage and increased gut permeability. This leaves the animal exposed and vulnerable to systemic infections. Bacterial translocation through the gut barrier can lead to septic shock due to prolonged systemic inflammation. Similarly, mycotoxins are toxic for the intestinal epithelial cells when ingested by animals and change the immune status of the animal. Mycotoxins are damaging the gut epithelium and hereby reducing the gut barrier function and gut integrity. In contrast to endotoxins, they have no antigenic properties, so cannot be recognized directly by antigen presenting cells. This means that they do not trigger inflammation directly. However, Toll-like Receptors on immune cells also recognize so called Damage-associated-molecular patterns (DAMP’s), which are released by damaged or dying host cells. Thus, by destroying the gut barrier and increasing the gut permeability, mycotoxins trigger an immune response. In addition, mycotoxins can enter the bloodstream and destroy immune cells leading to a lower pool of immune cells, i.e. immunosuppression. This leaves the animal vulnerable to secondary diseases. Therefore, we can conclude that both endotoxins and mycotoxins change the immune response and weaken the animals leading to detrimental performance losses. COMBAT WITH CLAY MINERALS In practice, clay minerals are routinely supplemented to the feed to adsorb mycotoxins and wash them away from the intestinal tract. The interaction Figure 1. Adsorption at pH 3, Desorption at pH 6.5 and total binding efficiency (Adsorption-Desorption) of a common clay mineral (Bentonite) against Aflatoxin B1, Fumonisin B1 and a LPS preparation. Inclusion of the clay was respectively 1kg/T, 2.5 kg/T and 2.5 kg/T. Ref. Trilogy.
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