ADSORPTION OF AFLATOXINS FROM A CULTURE ONTO DIFFERENT BENTONITES.

MAGNOLI A., M, ; DALCERO A.,. ; TORREZ SANCHEZ R.; CHIACCHERA S. M..

Congreso; Advances in Research on toxigenic fungi and mycotoxins in South America ensuring food and feed safety in a mycogloble context.; 2006

unrc

Coccidiosis is a parasitic disease, caused by protozoa resident in the intestinal epithelium, which occurs wherever animals arehoused in small areas that are contaminated with coccidial oocysts. Historically, poultry have shown the greatest susceptibility to coccidiosis, because of the intensive nature of most of the poultry industry. Coccidiosis is still one of the most important hazards for broiler industry. A variety of anticoccidial drugs have been developed in the past with the ionophorous antibiotics being the most extensively used group. In poultry, coccidiosis is caused by Eimeria spp., of which eight are known to cause serious clinical disease. The symptoms of coccidiosis in poultry may be one or more of the following: bloody diarrhoea, high mortality, reduction in feed and water intake, emaciation and loss of egg production. Much of the economic loss that is associated with coccidiosis is incurred prior to diagnosis. This makes prevention more important than treatment. Therefore, anticoccidials are commonly used feed additives in the poultry industry. On the other hand, the addition of non nutritive adsorbents in the animal diets in order to prevent for deleterious effects of aflatoxins is a common practice both for economical and healthy reasons. However, the adsorbent, which decreases the bioavailability of mycotoxins, can also sequester many nutrients and anticoccidials from the diets, reducing the performance of the animal. In the present report the competitive adsorption of monensin, an ionophorous antibiotic, and aflatoxin B1 is shown. Bentonite was chosen because it is frequently added to the animal feed to prevent aflatoxicosis and to act as pellet binder. The adsorption isotherm of Mn mimicking the physiological conditions, pH 2 and 39 oC, was investigated. A H-type isotherm was observed. Monensin is effectively capture by bentonite at least when is alone. The number of sites on the adsorbent surface is much lower than the one found for aflatoxin. On the other hand, aflatoxin B1 binds tightly to bentonite. Characteristic s-shaped isotherms were observed. A Fowler-Guggenheim isotherm fit indicates a cooperative adsorption mechanism, with attractive lateral interaction between aflatoxin molecules on the adsorbent surface. The irreversible nature of the process shows the chemical nature of the adsorption. The isotherm of aflatoxin was carried out in the presence of 55 ppm of Mn. The maximum adsorbent capacity for aflatoxin B1 decreases almost 25% in the presence of Mn. Although the reduction is remarkable at low AFB1 concentration it seems to be ameliorated when its concentration increase.