Sessions

In intensive pig farming, high livestock densities and stress caused by technological factors can promote the development of certain infections caused particularly by intestinal pathogens like E. coli and Salmonella species. The presence of these pathogens can damage the integrity of the intestinal barrier in pigs and increase oxidative stress. Gastrointestinal diseases often require antibiotic treatment and, in severe cases, can lead to death, resulting in reduced production and economic losses for the meat industry. The inappropriate use of antibiotics can contribute to the development of resistance, which is why the European Union has introduced strict regulations on their use, particularly regarding pro- and metaphylaxis in food-producing animals. It is crucial for the pig industry to find natural feed supplements that help maintain a healthy intestinal system in pigs or provide supportive effects that enhance the body’s ability to fight disease even after an infection has developed. One promising candidate is quercetin, a flavonoid compound with antimicrobial, antioxidant, and anti-inflammatory properties, which has been extensively investigated in scientific literature.

The aim of our study was to investigate the potential anti-inflammatory and antioxidant effects of quercetin on peripheral blood mononuclear cells (PBMCs) isolated from pig blood. We induced oxidative stress and inflammation in PBMC cultures using lipopolysaccharides derived from pathogenic E. coli and Salmonella and then examined the possible protective effect of quercetin. To determine the optimal treatment conditions for our experiments, we measured PBMC viability using the CCK assay. We monitored reactive oxygen species production using the DCFH-DA method and determined the levels of individual proinflammatory cytokines (IL-6 and IL-8) using ELISA method.

Our results confirmed that the model used is suitable for studying LPS-induced inflammation and oxidative stress. Our experiments demonstrated that quercetin, applied in vitro at concentrations of 25 and 50 μM, significantly reduced oxidative stress induced by E. coli and S. Typhimurium in PBMCs. We were able to induce increased IL-6 and IL-8 production with LPSs of different origins, but our experiments did not confirm an anti-inflammatory effect of quercetin. Our research may provide a basis for the development of a white blood cell–intestinal epithelial cell co-culture model, which can be used to study the effects of individual feed supplements in more detail.