Humic Acids Preparation, Characterization, and Their Potential Adsorption Capacity for Aflatoxin B1 in an In Vitro Poultry Digestive Model

Abstract

Vermicompost was used for humic acid (HA) preparation, and the adsorption of aflatoxin B1 (AFB1) was investigated. Two forms of HA were evaluated, natural HA and sodium-free HA (SFHA). As a reference, a non-commercial zeolitic material was employed. The adsorbents were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), energy-dispersive X-ray spectroscopy (EDS), zeta potential (ζ-potential), scanning electron microscopy (SEM), and point of zero charge (pHpzc). The adsorbent capacity of the materials when added to an AFB1-contaminated diet (100 µg AFB1/kg) was evaluated using an in vitro model that simulates the digestive tract of chickens. Characterization results revealed the primary functional groups in HA and SFHA were carboxyl and phenol. Furthermore, adsorbents have a highly negative ζ-potential at the three simulated pH values. Therefore, it appears the main influencing factors for AFB1 adsorption are electrostatic interactions and hydrogen bonding. Moreover, the bioavailability of AFB1 in the intestinal section was dramatically decreased when sorbents were added to the diet (0.2%, w/w). The highest AFB1 adsorption percentages using HA and SFHA were 97.6% and 99.7%, respectively. The zeolitic material had a considerable adsorption (81.5%). From these results, it can be concluded that HA and SFHA from vermicompost could be used as potential adsorbents to remove AFB1 from contaminated feeds.

Efficacy of water application of a humic substance, butyric acid, vitamins C, D, and E and/or electrolytes on performance and mortality in health-challenged nursery pigs¹

“…In a review article by Trckova et al (2005) , it was reported that humic substances can form chelated complexes with heavy metals, such as lead and mercury, and make them insoluble, thus they are excreted so no adverse effects occur in organisms. In addition, humic substances are highly effective in the adsorption of aflatoxin B 1 as was found in an in vitro poultry digestive model ( Maguey-González et al, 2023 ).…”

Therapeutic Efficiency of Humic Acids in Intoxications

“…as it represents a substance still in the process of humification, but with proven biological properties in vivo [152][153][154]. Even 97.6% and 99.7% adsorption capacity for AFB 1 were found for HAs and sodium-free HAs isolated from vermicompost in in vitro study [155]. Based on the detected effects and already mentioned properties of HAs, several mechanisms by which HAs bind aflatoxins have been proposed.…”