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

ZACHETTI, V.G.L.; 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 Project Ghent University

The aim of this study was to evaluate the occurrenceof several fungal metabolites, including mycotoxins in natural grasses(Poaceae) intended for grazing cattle. A total of 36 asymptomatic grassesbelonging to 9 different genera all included in the Poaceae family werecollected during 2016. Sixty different metabolites were detected. Among the fewmycotoxins considered toxic for ruminants, no samples of natural grasses werecontaminated with aflatoxins, ochratoxin A, ergot alkaloids, gliotoxin, and typeA 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 B1at low frequency. Other fungal metabolites that were found to be prevalent wereother Fusarium metabolites likebeauvericin, equisetin and aurofusarin, metabolites produced by Alternaria spp., sterigmatocystin andits precursors and anthrachinone derivatives such as emodin, chrysophanol and skyrin. Partialdegradation in the rumen does mean that they are less toxic to cattle than toother animals, but some of these degradation products can be more toxic thanthe original mycotoxin. There are some studies on synergistic effects and onlya few of them include those metabolites that were the most prevalent in ourstudy. So, it cannot be ruled out that low levels of several mycotoxins might bemore problematic than high levels of an individual mycotoxin, due to theirsynergistic relationship. Considering that this area of temperate grassland isused 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 ourcountry.