Aflatoxin Toxicity Reduction in Feed by Enhanced Binding to Surface-Modified Clay Additives

Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that more readily bind some contaminants than the untreated clay. Montmorillonites treated with organic cations, such as hexadecyltrimethylammonium (HDTMA) and phenyltrimethylammonium (PTMA), more effectively remove organic contaminants, such as benzene and toluene, from water than untreated clay. Similarly, montmorillonite treated with PTMA (Kd = 24,100) retained more aflatoxin B1 (AfB1) from aqueous corn flour than untreated montmorillonite (Kd = 944). Feed additives that reduced aflatoxin toxicity in animal feeding studies adsorbed more AfB1 from aqueous corn flour than feed additives that were less effective. The organic cations HDTMA and PTMA are considered toxic and would not be suitable for clay additives used in feed or food, but other non-toxic or nutrient compounds can be used to prepare surface-modified clays. Montmorillonite (SWy) treated with choline (Kd = 13,800) and carnitine (Kd = 3960) adsorbed much more AfB1 from aqueous corn flour than the untreated clay (Kd = 944). A choline-treated clay prepared from a reduced-charge, high-charge montmorillonite (Kd = 20,100) adsorbed more AfB1 than the choline-treated high-charge montmorillonite (Kd = 1340) or the untreated montmorillonite (Kd = 293). Surface-modified clay additives prepared using low-charge smectites and nutrient or non-toxic organic compounds might be used to more effectively bind aflatoxins in contaminated feed or food and prevent toxicity

Characterization of Three Deoxynivalenol Sulfonates Formed by Reaction of Deoxynivalenol with Sulfur Reagents

Reduction of the <i>Fusarium</i> mycotoxin deoxynivalenol (DON) in animal feed by treatment with sodium bisulfite and sodium metabisulfite has been successfully demonstrated in several studies. All of them reported formation of one DON sulfonate of strongly reduced toxicity compared to DON. The starting point of the present work was investigation of different sulfur reagents for reduction of DON. In the course of these experiments, three different DON sulfonates termed DON sulfonate 1 (<b>1</b>), DON sulfonate 2 (<b>2</b>), and DON sulfonate 3 (<b>3</b>) were identified and structurally elucidated by UHPLC–HRMS/MS as well as NMR spectroscopy. Compound <b>1</b> is characterized by loss of the epoxide group, and <b>2</b> by formation of a hemiketal. Compound <b>3</b> is an equilibrating mixture of two isomers, a ketone and a hemiketal. The MS/MS pattern can be used to differentiate the three DON sulfonates, despite their same mass and molecular formula. Investigation of parameters influencing formation and stability of DON sulfonates revealed that rapid formation of <b>1</b> and <b>2</b> occurs at alkaline pH, whereas at acidic pH, slow formation of <b>3</b> takes place, irrespective of the sulfur reagent used. Whereas <b>1</b> and <b>2</b> are stable across a broad pH range, <b>3</b> decomposes to DON, <b>1</b>, and <b>2</b> at alkaline pH. In addition, both <b>2</b> and <b>3</b> are unstable in solid form. The formation, characterization, and stability of three novel DON sulfonates with respect to results from previous studies are discussed, providing insights of relevance for detoxification of DON-containing animal feed