In vitro ed in vivo efficacy assessment of a new bentonite based material acting as a multi-mycotoxin binder

Bentonite-based products are selective in adsorbing mycotoxins, being quite effective for AFB1 and FB1, but ineffective for other mycotoxins (namely, ZEA, DON, T-2 and OTA). Within the framework of the European Project MycoKey (Grant Agreement No.678781), an innovative bentonite-based material (bio-organoclay) was developed to act as a multi-mycotoxin binder. A bentonite containing Na-smectite as major mineral was modified by an acid-activation process followed by a functionalization with an organic, non-toxic modifier. The process was optimized at lab level, and optimal conditions (geological origin and physico-chemical properties of smectites, type and concentration of chemical agents, temperature, time of contact) were identified. Under optimal conditions, the new bio-organoclay sequestered in vitro more than 95% of AFB1, FB1, OTA, and ZEA in a large range of pH values (3-9). The adsorptions of mycotoxins occurred simultaneously with high capacity and affinity as determined by isothermal adsorption studies. Thereafter, the bio-organoclay was tested for its efficacy in reducing the urinary excretion of mycotoxins in rats using the biomarker approach. AFM1, ZEA and its metabolites of phase I biotransformation (?-ZOL, ?-ZOL and ?-ZAL), OTA and FB1 were analyzed in urine by in-house validated UPLC methods. For each toxin, two groups of rats (0.3 kg, initial body weight) were considered: the first group was used as control (C) and received a single intragastric bolus containing the mycotoxin; the second group (T) received the mycotoxin supplemented with the bio-organoclay (0.5% w/w feed consumption). Rats were housed individually in metabolic cages to collect urine at different time points (4-72h for AFB1, ZEA and FB1; 4-320h for OTA). Normalized urinary excretion data of mycotoxins/metabolites were expressed as nmol mycotoxin/nmol creatinine and presented as mean±SD. Area under the curve (AUC0®t) over 72/320h and maximal urine concentration (Cmax) were calculated for target mycotoxins/metabolites and were used to compare control and treated groups. Results of toxicokinetic excretion of mycotoxins showed that the bio-organoclay significantly reduced urinary excretion of AFM1, ZEA, FB1 and OTA (P values < 0.05). The use of this bio-organoclay as feed additive can be considered a valid approach to reduce mycotoxins bioavailability in animals exposed to the main mycotoxins. This product can be considered safe, as it has been obtained using reagents that are listed in the European Union Register of Feed Additives (EC Regulation, No.1831/2003).