Zearalenone adsorption by a commercial seeweed meal (Lithothamnium sp.)

KELLY KELLER; CARINA PEREYRA; TATIANA ALMEIDA; LILIA CAVAGLIERI; CARLOS ROSA

Tulln, Austria

Congreso; Global discussion forum on:Worldwide Mycotoxin Reduction in Food and Feed Chains; 2009

International Society of Mycotoxicology

The aim of this work was to evaluate the effectiveness of a commercial seaweed meal in the ability for in vitro removal of zearalenone (ZEA). A solution of ZEA at 0; 0.5; 5; 10; 20 and 50 µg/ml in phosphate-buffered saline (PBS) at pH 2 and pH 6 was prepared. Seaweed meal (5 µg/ml) was incubated for 30 min at 37ºC with 1 ml PBS containing ZEA at different concentrations, separately. Seaweed meal was centrifuged and the supernatant containing unbound ZEA was collected. ZEA was quantified by HPLC with fluorescence detector. A theoretical model to explain the mechanism involved in the adsorption process was applied. This model allows estimation of two important parameters: the total number of adsorbent binding sites for ZEA (M) and the equilibrium constant (Keq) of the process. Both parameters allow determining the adsorbent efficiency (M x Keq). According to this adsorption model, the tested adsorbent had M values of 2.9 x 1014 and 8.3 x 1014 at pH 2 and pH 6, respectively. However, Keq value at pH 6 (3.9 x 106) was ten-fold higher than that at pH 2 (5 x 105), showing a higher efficiency at pH 6 (3.26 x 1021). Althoug the adsorbent efficacy is high at the both pH tested, this result showed the low reversibility of the adsorption process at pH 6. The level of adsorption of ZEA at pH 2 and pH 6 was 0.154 g and 0.44 g per gram of adsorbent. This high efficiency of seaweed meal demonstrates that it can be used not only as source of minerals (iron, calcium), vitamins (folic acid), antioxidants (α and β carotene), but also constitutes a potential candidate to be included in the diet of animals at risk of micotoxicosis.