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.

Assessment of the Impact of Humic Acids on Intestinal Microbiota, Gut Integrity, Ileum Morphometry, and Cellular Immunity of Turkey Poults Fed an Aflatoxin B1-Contaminated Diet

“…The observed benefits of HA on intestinal microbiota, gut integrity, ileal morphometry, and cellular immunity significantly strengthen the argument for their use as a practical and effective intervention against AFB 1 toxicity. These positive effects align with previous publications [ 12 , 13 ]. The improved villus height and width, indicative of enhanced nutrient absorption, corroborate the findings from Taklimi et al and López-García et al [ 14 , 15 ].…”

“…HA may also act as natural surfactants, increasing the permeability of cell membranes in bacteria, due to their amphiphilic character, which enhances the absorption of nitrogen and other micronutrients [ 20 ]. (B) Binding and detoxification of AFB 1 —HA have a high affinity for AFB 1 , binding to it mainly via hydrogen bonding and reducing its bioavailability in the intestine [ 12 ]. This effect reduces the toxicity of mycotoxin, protecting Firmicutes from its detrimental effects and potentially allowing them to thrive.…”

“…Previous in vitro studies demonstrated that HA have a strong affinity for AFB 1 due to their complex molecular structures. This binding reduces the amount of free AFB 1 molecules available for absorption, preventing their harmful effects on gut health and nutrient absorption [ 12 ]. Moreover, in another recent study, we confirmed the anti-inflammatory effects of HA on poults that received AFB 1 -contaminated feed [ 13 ]; those results are also associated with the immunomodulatory properties of HA on the CBH response.…”

“…Recent in vitro and in vivo studies have established the efficacy of humic acids (HA) in mitigating the detrimental effects of AFB 1 in turkey poults. These benefits include an improved performance and a significant reduction in aflatoxicosis severity [ 12 , 13 ]. Given the promising findings regarding the benefits of HA in mitigating AFB 1 toxicity in poultry, the present study aimed to assess the impact of dietary HA supplementation on various aspects of turkey poult health (intestinal microbiota, gut integrity, ileum morphometry, and cellular immunity) when fed an AFB 1 -contaminated diet.…”

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.…”