**Natalia Skiepko 1, Barbara Przybylska-Gornowicz 1, Magdalena Gaj ˛ecka 2, Maciej Gaj ˛ecki <sup>2</sup> and Bogdan Lewczuk 1,\***


Received: 29 June 2020; Accepted: 17 July 2020; Published: 20 July 2020

**Abstract:** The purpose of this study was to determine the effects of single and combined administrations of deoxynivalenol (DON) and zearalenone (ZEN) on the histology and ultrastructure of pig liver. The study was performed on immature gilts, which were divided into four equal groups. Animals in the experimental groups received DON at a dose of 12 μg/kg body weight (BW) per day, ZEN at 40 μg/kg BW per day, or a mixture of DON (12 μg/kg BW per day) and ZEN (40 μg/kg BW). The control group received vehicle. The animals were killed after 1, 3, and 6 weeks of experiment. Treatment with mycotoxins resulted in several changes in liver histology and ultrastructure, including: (1) an increase in the thickness of the perilobular connective tissue and its penetration to the lobules in gilts receiving DON and DON + ZEN; (2) an increase in the total microscopic liver score (histology activity index (HAI)) in pigs receiving DON and DON + ZEN; (3) dilatation of hepatic sinusoids in pigs receiving ZEN, DON and DON + ZEN; (4) temporary changes in glycogen content in all experimental groups; (5) an increase in iron accumulation in the hepatocytes of gilts treated with ZEN and DON + ZEN; (6) changes in endoplasmic reticulum organization in the hepatocytes of pigs receiving toxins; (7) changes in morphology of Browicz–Kupffer cells after treatment with ZEN, DON, and DON + ZEN. The results show that low doses of mycotoxins used in the present study, even when applied for a short period, affected liver morphology.

**Keywords:** zearalenone; deoxynivalenol; mycotoxins; histology; ultrastructure; pig; hepatocyte; liver

**Key Contribution:** Low doses of deoxynivalenol and zearalenone induce significant changes in hepatocytes, Browicz–Kupffer cells, and perilobular connective tissue.
