Revision of current concepts of tannins impact on gastrointestinal tract homeostasis in piglets.

• Applicant: Professor Dr. Jürgen Zentek
• Subject Area: Veterinary Medical Science
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 465494444

Tannins are considered as anti-nutritional factors in monogastric animals nutrition with attributed negative effects on feed intake, nutrient digestibility and performance. On the other hand, certain tannin-containing plant materials are well known for their anti-diarrheal properties. Diarrhea among post-weaning piglets is one of the most important health conditions in pig farming. Piglets are susceptible to infection by enteropathogens, the most important being enterotoxigenic Escherichia coli (ETEC). Extensive antibiotics use in prevention and therapy of infections in animals significantly contributed to spread of antimicrobial resistance, and in consequence restrictions on their use in farming. As the consequence, the development of preventive and therapeutic strategies targeted on maintaining piglets gut health, which are based on novel mechanisms, is urgently needed. Biological activities of ellagitannins (hydrolysable tannins) contained in Lythrum salicaria L. herb (LSH) as well as their gut microbiota metabolites- urolithins have put a new light on the potential impact of tannins on gastrointestinal health of post-weaning piglets. LSH and contained ellagitannins were shown to stimulate intestinal epithelial cells monolayer formation, while metabolites produced by piglets gut microbiota inhibited inflammatory response of immune cells. LSH was also shown to inhibit ETEC growth and adhesion to epithelial cells, but was not negatively affecting gut microbiota diversity. The results of these in vitro studies indicated promising biological properties which could be utilized maintaining intestinal homeostasis and prevention of ETEC infections resulting in post-weaning diarrhea in piglets. Faba beans are well known for their anti-nutritional properties attributed to high level of condensed tannins of unknown structure (which are mainly cumulated in their pods). However, hitherto studies have not included the phytochemical examination and the dosage of ingested tannins has not been precisely controlled. On the other hand, plant materials containing condensed tannins are known for their anti-microbial and anti-diarrheal properties, while studies on their microbial metabolism in the intestinal tract put a new light on the factors triggering their biological activity following oral application. Above aspects and recent phytochemical screening studies allow to reasonably assume that faba bean pods (FBP) contain condensed tannins of interesting structural features, which biological properties following controlled intake may occur beneficial for intestinal health of piglets. The aim of the proposal is to address the paradigm of the anti-nutritional properties of tannins by verification of the general hypothesis, that hydrolysable and condensed tannins contained in LSH and FBP can improve intestinal homeostasis, beneficially influence intestinal microbiota as well as prevent ETEC infections, without expressing negative effects on piglets’ health status.

• DFG Programme: Research Grants
• International Connection: Poland
• Cooperation Partner: Privatdozent Jakub Piwowarski, Ph.D.