MYCOTOXIN CONTAMINATION IN NATURAL GRASSES (POACEAE) INTENDED FOR GRAZING CATTLE IN ARGENTINA

ZACHETTI, V.G.; NICHEA, M.J.; SULYOK, M.; TORRES, A.M.; CHULZE, S,N,; RAMIREZ, M. L

Ghent

Congreso; 1st MYCOKEY International Conference Global Mycotoxin Reduction in the Food and Feed Chain; 2017

Mycokey Horizont 2020- Ghent University

The aim of this study was to evaluate the occurrence of several fungal metabolites, including mycotoxins in natural grasses (Poaceae) intended for grazing cattle. A total of 36 asymptomatic grasses belonging to 9 different genera all included in the Poaceae family were collected during 2016. Sixty different metabolites were detected. Among the few mycotoxins considered toxic for ruminants, no samples of natural grasses were contaminated with aflatoxins, ochratoxin A, ergot alkaloids, gliotoxin, and type A trichothecenes, among others. However, we were able to detect important metabolites (toxic to ruminants) such as zearalenone (up to 5.3 μg/kg) and fumonisin B1 at low frequency. Other fungal metabolites that were found to be prevalent were other Fusarium metabolites like beauvericin, equisetin and aurofusarin, metabolites produced by Alternaria spp., sterigmatocystin and its precursors and anthrachinone derivatives such as emodin, chrysophanol and skyrin. Partial degradation in the rumen does mean that they are less toxic to cattle than to other animals, but some of these degradation products can be more toxic than the original mycotoxin. There are some studies on synergistic effects and only a few of them include those metabolites that were the most prevalent in our study. So, it cannot be ruled out that low levels of several mycotoxins might be more problematic than high levels of an individual mycotoxin, due to their synergistic relationship. Considering that this area of temperate grassland is used for grazing cattle all year long due to the richness in palatable grasses (Poaceae), the present work represents the second study on this subject in our country.