In vitro and in vivo characterization of mycotoxin-binding additives used for animal feeds in Mexico

Abstract

The study was conducted to characterize and compare twelve different additives distributed in Mexico as mycotoxin binders utilizing: (1) equilibrium isothermal analysis for aflatoxin B₁ (AFB₁) adsorption, (2) a variety of mineralogical probes, and (3) Hydra toxicity bioassay. The test additives Milbond-TX® (MLB), Mycoad® (MCA), Volclay FD181® (VOL), Fixat® (FXT), Toxinor® (TOX), Mexsil® (MEX), Mycosil® (MYC), Klinsil® (KLS), Zeotek® (ZEO), Duotek® (DUO), Mycosorb™ (MSB), and Mycofix® Plus 3.0 (MIX) were compared with NovaSil™ Plus (NSP). Isotherms for AFB₁ adsorption were conducted at pH 2 and pH 6.5, mimicking pH conditions in the stomach and small intestine. Mineralogical analysis included determination of swelling volume, X-ray diffraction analysis, and fractionation procedures. A Hydra vulgaris toxicity study was performed to evaluate the potential safety of the additives. Computer-generated isotherm data were fit using the Langmuir model, and parameters of Q _max and K _d were estimated. The most effective additives for AFB₁ at both pH conditions were NSP, MLB, MCA and VOL, while the least effective was MSB. The amounts of sand, silt and clay fractions varied among the additives. Nine of the additives showed the presence of smectite. Most of the additives were found to be non-toxic to Hydra except for the organoclays (ZEO, DUO) and MSB. In general, NSP demonstrated the highest sorption capacity in the bulk material and the different fractions. Studies to characterize these binding additives further and to evaluate their multiple mycotoxin sorption claims are ongoing.

Keywords:

• aflatoxin
• mycotoxins
• binding additives
• binders
• isothermal analysis
• adsorption
• smectite

Acknowledgements

This research was supported by USAID LAG-G-00-96-90013-00 and NIH P42 ES04917 Grants and a PROMEP/UANL Mexico fellowship.