Structural Characteristic of commercial Bentonites and its in vivo performance as detoxifier against Aflatoxin B1 in poultry.

A. MAGNOLI; L. TALLONE; A. ASTORECA; A. M. DALCERO; C. A. DA ROCHA ROSA; R. D. MIAZZO; M. PERALTA; M. SALVANO; R. M. TORRES SANCHEZ; S. M. CHIACCHIERA

Carlos Paz

Conferencia; Advances in research on toxigenic fungi and mycotoxins in South America ensuring food and feed safety in a myco-globe context. Myco-Globe.; 2006

Universidad de Rio Cuarto

One approach to the detoxification of mycotoxins is use of non-nutritive absorptive materials in anima diets to reduce the absorption of mycotoxins from the gastrointestinal tract of chickens, swines and pigs among others. In vitro and in vivo studies have demonstrated the effectiveness of a natural sodium bentonite (SB) to adsorb AFB1 from aqueous solution: An inert stable and insoluble complex between SB and AFB1, was assumed to be the responsible fro preventing toxin absorption in the intestine. Also in vitro studies with synthetic zeolite NaA showed that FB1 can significantly reduce the efficacyof the sorbent to sequester AFB1. Addition of high specific surface area synthetic zeolite was also found to improve the productive parameters under acute AFB1 poultry exposure. Previous in vitro studies had demonstrated a stong ph dependence of the NaA zeolite AFB1-binding ability. In fact the mayor adsorption observed a pH twof became negligible when the pH was raced to six. An initial protonation followed by hydroxyl ligand exchange might be operating, in great analogy as the proposed inner-sphere complexation of a ligand in clinoptilolita. Based of the pH dependence and Fourier Transform IR spectroscopy of the AFB1-complx with the zeolite, chelation of the toxin carbonyl groups with the metal ions or metal surface sites at low pH was claimed to be responsible for the observed strong interaction. This type of interaction was first proposed by Grant and Phillips for hydrated Na-Ca-aluminosilicate clay. Due to the low cost and high specific surface area developed by montmorillonites, commercial smectites were added to the chicken diets. The effectivity of these clays as detoxifiers may vary from one geological deposit o another even with the batch from a given source. Bentonites show two types of sites available for adsorption: structural isomorphic substitutions originate negative binding sites at the interlayer in a wide pH range, and ampholitic surface hydroxyls, responsible for metal surface complexation, allowed retaining different cations and molecules. Due to the economical importance of the use of these commercial smectites, not only as detoxifiers but also as binding agent for pellets formation, initial attention is paid to the mineral composition, morphological, strucutara and surface charge. Clay surface interactions depend on the nature of the isomorphous substitution in the lattice, surface area, pore size distribution and porosity of montmorillonite. Changes in pH also affect the morphological characteristic of the clays. The aim of the present research was to compare the structural characteristic of three bentonites with its AFB1 binding ability.