Adsorption of modified halloysite nanotubes in vitro and the protective effect in rats exposed to zearalenone.

The aim of the present study was to investigate the sorption properties in vitro and the application feasibility of modified halloysite nanotubes (HNT) in reducing the toxic effect of ZEN in rats in vivo. HNT were modified using the surfactant stearyldimethylbenzylammonium chloride. Modified HNT (MHNT) was evaluated using electron microscopy, which revealed that the modification had successfully enlarged the nanotube inner diameter from 11.35 to 20.12 nm. In an in vitro study, the efficiency of MHNT to adsorb zearalenone (ZEN) from simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) was investigated in comparison with HNT or a montmorillonite mixture (MON). For all tested adsorbents, the adsorption efficiency for ZEN was increased when the adsorbent dose rose from 0.4 to 1.0 mg/ml and became stable beyond this dose. Moreover, the ZEN adsorption increased with the extension of adsorption times from 20 to 90 min (SGF) and from 30 to 120 min (SIF) without further increase afterwards. Already at the first measuring times (20 and 30 min for SGF and SIF, respectively) MHNT showed a higher adsorptive property then HNT. The ability of MHNT to prevent lesions caused by ZEN was evaluated in 60 female rats. The rats received five experimental diets for two weeks: Control (per kg diet 0.001 mg ZEN); ZEN (0.5 mg ZEN), HNT (0.5 mg ZEN + 1% HNT), MHNT (0.5 mg ZEN + 1% MHNT) and MON (0.5 mg ZEN + 1% MON). The results indicated that the tested adsorbents mitigated toxic and estrogenic effects of ZEN exposure including changes in oxidative stress biomarkers and organ weights. In some parameters (gain, oestradiol content in serum and ZEN concentration in reproductive organs), MHNT exceeded the effectiveness of HNT. Thus, it can be concluded that the modification enhances the adsorbent properties of HNT and that MHNT can bind to ZEN in animal feed or in the gastrointestinal tract.