*Article* **Carry-Over of Zearalenone and Its Metabolites to Intestinal Tissues and the Expression of CYP1A1 and GST**π**1 in the Colon of Gilts before Puberty**

**Magdalena Mróz 1 , Magdalena Gaj˛ecka 1,\* , Paweł Brzuzan <sup>2</sup> , Sylwia Lisieska-Zołnierczyk ˙ <sup>3</sup> , Dawid Leski <sup>4</sup> , Łukasz Zielonka <sup>1</sup> and Maciej T. Gaj˛ecki <sup>1</sup>**


**Abstract:** The objective of this study was to evaluate whether low doses of zearalenone (ZEN) affect the carry-over of ZEN and its metabolites to intestinal tissues and the expression of CYP1A1 and GSTπ1 in the large intestine. Prepubertal gilts (with a BW of up to 14.5 kg) were exposed in group ZEN to daily ZEN5 doses of 5 µg/kg BW (*n* = 15); in group ZEN10, 10 µg/kg BW (*n* = 15); in group ZEN15, 15 µg/kg BW (*n* = 15); or were administered a placebo (group C, *n* = 15) throughout the experiment. After euthanasia, tissues were sampled on exposure days 7, 21, and 42 (D1, D2, and D3, respectively). The results confirmed that the administered ZEN doses (LOAEL, NOAEL, and MABEL) were appropriate to reliably assess the carry-over of ZEN. Based on the observations made during 42 days of exposure to pure ZEN, it can be hypothesized that all mycotoxins (ZEN, α-zearalenol, and β-zearalenol) contribute to a balance between intestinal cells and the expression of selected genes encoding enzymes that participate in biotransformation processes in the large intestine; modulate feminization processes in prepubertal gilts; and elicit flexible, adaptive responses of the macroorganism to mycotoxin exposure at the analyzed doses.

**Keywords:** zearalenone; low dose; intestines; carry-over; CYP1A1 and GSTπ1; prepubertal gilts

**Key Contribution:** Zearalenone mycotoxicosis in a dose of MABEL plays a beneficial role in the processes of somatic development of prepubertal gilts, which is important for breeders. The question arises—should one perform ZEN detoxification in doses of MABEL in feed materials or animal feed?
