Tri-octahedral bentonites as potential technological feed additive for Fusarium mycotoxin reduction

In 2009 the EU Regulation 386/2009 established a new functional group of feed additives called "substances for reduction of the contamination of feed by mycotoxin". Later, di-octahedral bentonite (1 m558) was authorised, as an anti-aflatoxin additive, being the only additive of this group authorised to date. This work aims to demonstrate the effectiveness of other bentonites, such as tri-octahedral bentonites, versus Fusarium-mycotoxins, since very few adsorbents have proved their effectiveness in relation to this group of mycotoxins. For this purpose, 7 bentonites (six of them tri-octahedral) and 7 commercial adsorbents, added at 0.02% (w/v), were assayed in an in vitro adsorption experiment using two simulated gastro-intestinal (GI) juices (pH 1.3 and 6.8) versus zearalenone (ZEN: 0.1-5 mg/L), fumonisin B₁ (FB₁: 1-10 mg/L) and deoxynivalenol (DON: 2-10 mg/L). Mycotoxin adsorption data were fitted to Langmuir and Freundlich isotherms. In vitro adsorption experiments showed that ZEN and FB₁ (in the latter case only in acid medium) were partially adsorbed, while the adsorption of DON was negligible. Moreover, the increase of adsorbent dose (up to 0.20%, w/v) significantly improved the in vitro adsorption of ZEN and FB₁, reaching >90% of adsorption. The present work proposes the use of some tri-octahedral bentonites as feed additives for Fusarium-mycotoxin reduction.