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Resumen La presencia de micotoxinas en alimentos es un problema de gran importancia a nivel mundial que provoca serios perjuicios sanitarios y económicos. Para limitar los efectos de las micotoxinas a los animales uno de los métodos más utilizados es la aplicación de secuestrantes. Estos son polímeros inorgánicos u orgánicos que al añadirse a los alimentos forman complejos con las micotoxinas en la luz intestinal disminuyendo así su absorción. Por este motivo se evaluó la eficacia de cuatro secuestrantes, dos alumino silicatos hidratados de calcio y sodio, uno de glucomananos esterificados y otro del tipo multi modular para aflatoxina B1 (AFB1). La capacidad de adsorción fue evaluada in vitro y bajo condiciones de pH similares a las del tracto gastrointestinal de los animales. La concentración de AFB1 fue determinada mediante cromatografía líquida de alta resolución (HPLC). Con la excepción del producto de glucomananos esterificados, el porcentaje de unión de aflatoxina B1 obtenido para los secuestrantes estudiados fue alto (> 76%). Estos resultados sugieren que la mayoría de los secuestrantes utilizados en este estudio son potenciales agentes químicos-biológicos que podrían ser utilizados para disminuir los efectos de las aflatoxinas en animales Summary The contamination of animal feed with mycotoxins represents a worldwide problem that causes serious diseases in animals and economic losses. One of the most used methods for protecting animals against mycotoxins is the utilization of adsorbents. These are inorganic or organic components that added to foods form complexes with mycotoxins in the gastrointestinal tract thus decreasing its absorption. Four mycotoxin binder products including two hydrated sodium calcium aluminosilicates, one esterified glucomannan and one multi modular were used to determine their efficacity to bind aflatoxin B1. The binding ability for AFB1 was conducted by an in vitro assay, which simulated the pH condition of the gastrointestinal tract of animals. AFB1 contents was determinated by high performance liquid chromatographic (HPLC). With the exception of the esterified glucomannan product, the binding percent of AFB1 was high (> 76%) by the sequestering agents used in the current study. These results suggest that most commercial adsorbent products used in this study are potential chemical - biological agents that might be used to decrease the effects of aflatoxins in animals.

Species belonging to Aspergillus section Flavi occur naturally in crops and can cause food spoilage and/or toxin production. The aim of this study was to determine the occurrence and diversity of the species of Aspergillus section Flavi found in wheat and sorghum at harvest time and during silage storage, and to evaluate the toxigenic potential of the isolates to determine the contamination risk of mycotoxins in grains. Strains from Aspergillus flavus and Aspergillus parasiticus were found based on multi-gene phylogenetic analyses. This is the first report on the presence of A. parasiticus in wheat from Uruguay. Of the 80 isolates Aspergillus section Flavi, 30% produced aflatoxins (AFs), mainly type B1, and 25% produced cyclopiazonic acid (CPA). Within the isolates from wheat samples, 35% were AFs producers and 27.5% were CPA producers. Among the Aspergillus section Flavi isolates from sorghum, 25% were AFs producers while 22.5% were CPA producers. This work contributes to the knowledge of the species in crops and helps define appropriate strategies for the prevention and control of contamination with AFs and CPA by Aspergillus section Flavi fungi.

Fusarium graminearum sensu stricto (F. graminearum s.s.) is the major causal agent of Fusarium head blight of wheat worldwide, and contaminates grains with trichothecene mycotoxins that cause serious threats to food safety and animal health. An important aspect of managing this pathogen and reducing mycotoxin contamination of wheat is knowledge regarding its population genetics. Therefore, isolates of F. graminearum s.s. from the major wheat-growing region of Uruguay were analyzed by amplified fragment length polymorphism assays, PCR genotyping, and chemical analysis of trichothecene production. Of the 102 isolates identified as having the 15-ADON genotype via PCR genotyping, all were DON producers, but only 41 strains were also 15-ADON producers, as determined by chemical analysis. The populations were genotypically diverse but genetically similar, with significant genetic exchange occurring between them. Analysis of molecular variance indicated that most of the genetic variability resulted from differences between isolates within populations. Multilocus linkage disequilibrium analysis suggested that the isolates had a panmictic population genetic structure and that there is significant recombination occurs in F. graminearum s.s. In conclusion, tour findings provide the first detailed description of the genetic structure and trichothecene production of populations of F. graminearum s.s. from Uruguay, and expands our understanding of the agroecology of F. graminearum and of the correlation between genotypes and trichothecene chemotypes.