Assessing the <i>in vitro</i> efficiency in adsorbing mycotoxins of a tri-octahedral bentonite with potential application in aquaculture feed

The use of mycotoxin binders in feed products is currently the most efficient method to mitigate the harmful effects of mycotoxins. The unprecedented growth of aquaculture in recent years has led to an increased use of plant-based ingredients in fish feeds, thereby raising the risk of mycotoxin exposure. This study investigates the <i>in vitro</i> adsorption efficiency of a tri-octahedral bentonite against aflatoxin B₁ (AFB1), zearalenone (ZEN), and fumonisin B₁ (FB1) in simulated gastric (pH = 1.2) and intestinal (pH = 6.8) fluids at 25 °C, the usual body temperature in aquaculture fish species. The binder was highly effective, removing over 98% of AFB1 from both media. FB1 was completely adsorbed at pH = 1.2, while its adsorption at pH = 6.8 reached a maximum of 46.3%. ZEN binding was consistent across both pH levels, ranging from 56.1% to 69.7%. Nine equilibrium isotherm functions were fitted to the experimental data to elucidate the adsorption mechanisms. A Sips model isotherm best characterized AFB1 adsorption in simulated gastric fluid, whereas that of ZEN was best described by the Freundlich model. In simulated intestinal fluid (pH = 6.8), monolayer adsorption described by the Langmuir model provided the best fit for all three mycotoxins.