Sessions

Nowadays, for the swine industry, which faces ever-increasing consumer demands, it is crucial to mitigate diseases associated with oxidative stress and inflammatory processes while maximizing productivity. Adhering to the "One Health" approach and guidelines aimed at minimizing antimicrobial resistance, efforts must also be made to reduce antibiotic usage; the application of beneficial feed additives – such as flavonoids – can serve as an effective tool in this regard. Quercetin, the subject of our research, is a widely studied and readily available flavonoid with well-documented antioxidant and immunomodulatory effects in both human and animal studies. However, limited information is currently available regarding the effects of quercetin on porcine white blood cells.

During the first stage of our research, we treated porcine peripheral blood mononuclear cells (PBMCs) with lipoteichoic acid (LTA) derived from Gram-positive bacteria (Staphylococcus aureus) and with two types of plant lectins (concanavalin A, ConA; phytohemagglutinin, PHA) to induce oxidative stress and inflammation (IL-6 and IL-8 production). Subsequently, we treated the cells with quercetin to investigate its potential antioxidant and anti-inflammatory activity by mitigating these adverse effects. Treatment concentrations and durations (24 and 48 hours) safe for the cells were determined beforehand by measuring metabolic activity (using CCK-8 and LDH assays). Intracellular reactive oxygen species (ROS) levels were measured using the DCFH-DA assay, while the level of inflammatory markers (IL-6 and IL-8) was determined via ELISA.

In the assessment of oxidative stress, LTA, ConA, and PHA all resulted in a significant increase in ROS production. Combination treatment with quercetin reduced ROS levels in almost all cases, demonstrating the well-documented antioxidant effect of quercetin. In contrast, neither LTA nor the lectins elicited consistent IL-6 and IL-8 production in the cells (except for increased IL-6 production following 48-hour ConA and PHA treatment). No significant changes in the investigated interleukin levels were observed in connection with the quercetin combination treatments.

Based on the results obtained, we can conclude that since we were able to induce ROS production in porcine PBMC cells using various stimuli, this species-specific in vitro model is a suitable option for the reliable study of oxidative stress and for demonstrating the antioxidant effects of alternative compounds, such as quercetin. Further research is required regarding the cytokine production of PBMC cells and the immunomodulatory effects of quercetin (specifically, measuring the production of other key immunological markers such as IL-10 and TNF-α).