*Article* **Does Deoxynivalenol Affect Amoxicillin and Doxycycline Absorption in the Gastrointestinal Tract? Ex Vivo Study on Swine Jejunum Mucosa Explants**

**Marta Mendel 1,\* , Wojciech Karlik <sup>1</sup> , Urszula Latek <sup>1</sup> , Magdalena Chłopecka <sup>1</sup> , Ewelina Nowacka-Kozak <sup>2</sup> , Katarzyna Pietruszka <sup>2</sup> and Piotr Jedziniak <sup>2</sup>**


**Abstract:** The presence of deoxynivalenol (DON) in feed may increase intestinal barrier permeability. Disturbance of the intestinal barrier integrity may affect the absorption of antibiotics used in animals. Since the bioavailability of orally administered antibiotics significantly affects their efficacy and safety, it was decided to evaluate how DON influences the absorption of the most commonly used antibiotics in pigs, i.e., amoxicillin (AMX) and doxycycline (DOX). The studies were conducted using jejunal explants from adult pigs. Explants were incubated in Ussing chambers, in which a buffer containing DON (30 µg/mL), AMX (50 µg/mL), DOX (30 µg/mL), a combination of AMX + DON, or a combination of DOX + DON was used. Changes in transepithelial electrical resistance (TEER), the flux of transcellular and intracellular transport markers, and the flux of antibiotics across explants were measured. DON increased the permeability of small intestine explants, expressed by a reduction in TEER and an intensification of transcellular marker transport. DON did not affect AMX transport, but it accelerated DOX transport by approximately five times. The results suggest that DON inhibits the efflux transport of DOX to the intestinal lumen, and thus significantly changes its absorption from the gastrointestinal tract.

**Keywords:** deoxynivalenol; amoxicillin; doxycycline; Ussing chamber; swine jejunum mucosa explants

**Key Contribution:** DON does not affect AMX transport but inhibits the efflux transport of DOX to the intestinal lumen, and thus significantly changes the kinetics of DOX absorption from the gastrointestinal tract.
