Effects of Lactobacillus rhamnosus DSM7133 on Intestinal Porcine Epithelial Cells

SIMPLE SUMMARY: Salmonella species and Escherichia coli infections in pigs can result in substantial economic losses and frequently necessitate antibiotic treatment. The misuse of antibiotics has led to the emergence of antibiotic resistance, and residues in the human food chain may appear. It is pivotal for the swine industry to seek feed additives that can contribute to the health of the gastrointestinal tract. Probiotics are promising candidates for this purpose. Probiotic bacteria offer various advantageous effects, including the prevention of pathogen adhesion, the promotion of heat shock proteins, the modulation of cytokine production, antioxidative qualities, and the reinforcement of barrier function. The beneficial effect of probiotics is species/strain specific; the potential benefits need to be individually assessed for each probiotic strain or species. The objective of this study was to investigate the impact of Lactobacillus rhamnosus in in vitro porcine gastrointestinal infection models. Two economically significant swine pathogens, namely Escherichia and Salmonella enterica serovar Typhimurium, were applied to model gastrointestinal infections. L. rhamnosus demonstrated numerous advantageous effects, such as its antioxidative properties, ability to inhibit pathogens, anti-inflammatory characteristics, and capacity to enhance barrier function. This study makes a substantial contribution to the understanding of the specific advantageous effects associated with L. rhamnosus (which has relevance when choosing a probiotic in practice) and serves as a basis for further in vivo research. ABSTRACT: Antimicrobial resistance is one of the biggest health challenges nowadays. Probiotics are promising candidates as feed additives contributing to the health of the gastrointestinal tract. The beneficial effect of probiotics is species/strain specific; the potential benefits need to be individually assessed for each probiotic strain or species. We established a co-culture model, in which gastrointestinal infection was modeled using Escherichia coli (E. coli) and Salmonella enterica serovar Typhimurium (S. enterica serovar Typhimurium). Using intestinal porcine epithelial cells (IPEC-J2), the effects of pre-, co-, and post-treatment with Lactobacillus (L.) rhamnosus on the barrier function, intracellular (IC) reactive oxygen species (ROS) production, proinflammatory cytokine (IL-6 and IL-8) response, and adhesion inhibition were tested. E. coli- and S. Typhimurium-induced barrier impairment and increased ROS production could be counteracted using L. rhamnosus (p < 0.01). S. Typhimurium-induced IL-6 production was reduced via pre-treatment (p < 0.05) and post-treatment (p < 0.01); increased IL-8 secretion was decreased via pre-, co-, and post-treatment (p < 0.01) with L. rhamnosus. L. rhamnosus demonstrated significant inhibition of adhesion for both S. Typhimurium (p < 0.001) and E. coli (p < 0.001 in both pre-treatment and post-treatment; p < 0.05 in co-treatment). This study makes a substantial contribution to the understanding of the specific benefits of L. rhamnosus. Our findings can serve as a basis for further in vivo studies carried out in pigs and humans.