Nowadays, antimicrobial resistance is among the major challenges of human- and veterinary medicine. For this reason, there is a growing interest to replace the use of various antibiotics by different natural alternatives. The gastrointestinal tract provides a physical barrier to the diffusion of foreign materials from the lumen into the circulatory systems. Impairment of the intracellular tight junction shield, which is the major determinant of intestinal barrier function, is associated with various diseases. Infections caused by pathogen bacteria and inflammation diseases developed because of oxidative stress are led to serious economic and health problems. A functional in vitro model of the small intestine mimicking oxidative stress and pathogen-induced inflammation has been developed using IPEC-J2 healthy porcine epithelial cells. Protective effects of compounds of natural origin (e.g. metabolites of probiotic bacteria, plant extracts, polyphenols) can be tested in intestinal epithelial cells under the above-mentioned conditions. Our aim is to find alternatives which can be used as supplements in food-producing animals to the decrease of antibiotic consumption and the development of resistance against antibiotics.