**Kazimierz Obremski 1,\*, Wojciech Trybowski 2, Paweł Wojtacha 3,\*, Magdalena Gaj ˛ecka 1, Józef Tyburski <sup>4</sup> and Łukasz Zielonka <sup>1</sup>**


Received: 17 April 2020; Accepted: 25 May 2020; Published: 27 May 2020

**Abstract:** The aim of the present study was to determine the effect of zearalenone (ZEN), administered *per os* to gilts at doses equivalent to 50%, 100%, and 150% of no-observed-adverse-effect level (NOAEL) values for 14, 28, and 42 days during weaning, on changes in the parameters of the oxidoreductive balance, cytokine secretion, and basal metabolism in ileal Payer's patches. Immunoenzymatic ELISA tests and biochemical methods were used to measure the concentrations of interleukin 1α, interleukin 1β, interleukin 12/23p40, interleukin 2, interferon γ, interleukin 4, interleukin 6, interleukin 8, tumor necrosis factor α, interleukin 10, transforming growth factor β, malondialdehyde, sulfhydryl groups, fructose, glucose, and proline, as well as the activity of peroxidase, superoxide dismutase and catalase. The study demonstrated that ZEN doses corresponding to 50%, 100%, and 150% of NOAEL values, i.e., 5 μg, 10 μg, and 15 μg ZEN/kg BW, respectively, have proinflammatory properties, exacerbate oxidative stress responses, and disrupt basal metabolism in ileal Payer's patches in gilts.

**Keywords:** zearalenone; pre-pubertal gilts; GALT; oxidative stress; cytokine; metabolism

**Key Contribution:** This is the first ever study to investigate the influence of ZEN administered *per os* at NOAEL concentrations on the maintenance of homeostasis in the intestinal immune system of gilts during weaning. The results indicate that ZEN exerts proinflammatory effects, initiates the mechanism of oxidative stress in GALT, and modulates intestinal epithelial function by inducing changes in the metabolism of sugars and amino acids.
