Joint International Conference on Long-term Experiments ...

MYCOTOXINS CONTAMINATION IN FRESH AND SILAGE
OF ALFALFA (Medicago sativa)
B. Gálik, D. Bíro, M. Juráček, M. Šimko, J. Michálková
Slovak University of Agriculture, Department of Animal Nutrition, Nitra,
Slovak Republic
ABSTRACT
The aim of this work was detection of mycotoxin contamination in fresh alfalfa (dry
matter: 228 g.kg -1 ) and in alfalfa silage. Ensiled matter was wilted at six hours. Dry
matter content was 277.7 g.kg -1 in silage. Concentrations of mycotoxins
(deoxynivalenol 5/5, fumonisin, T-2 toxin, aflatoxin and ochratoxin) were determined
in fresh forage and silage of alfalfa. This was used immuno-enzymatic analysis by
ELISA Reader (Noack, Slovak Republic) for investigation amount of mycotoxins.
Concentrations of mycotoxins were higher in silage in comparison with concentrations
of mycotoxins in fresh matter.
The value of deoxynivalenol (DON) was 100 μg.kg -1 in fresh matter and 233.3
μg.kg -1 (average concentration) after conservation. We found 61.9 μg.kg -1 of fumonisin
after conservation and 51.2 μg.kg -1 in fresh matter. The content of T-2 toxin was 21.9
μg.kg -1 before ensiling and 88.5 μg.kg -1 in silage of alfalfa (minimum was 72.3 μg.kg -1
and maximum was 99.2 μg.kg -1 ). Contents of mycotoxins were produced by storage
fungi (aflatoxin and ochratoxin) were higher in silage than numbers of mycotoxins in
fresh alfalfa. Concentrations of all detected mycotoxins were lower than critical values.
Keywords: mycotoxins, contamination, fresh matter, silage, alfalfa
INTRODUCTION
Mycotoxins are toxic secondary metabolites produced by fungi. There are hundreds of
mycotoxins known, but few have been extensively researched and even few have good
methods of analysis available (Nelson et al., 1993, Nedělník, Moravcová, 2006).
Mycotoxins exhibit a variety of biological effects in animals: liver and kidney toxicity,
central nervous system effects and estrogenic effects, to name a few (Whitlow et al.
1998). Worldwide, approximately 25% of crops are affected by mycotoxins annually.
Many different mycotoxins have been found to occur on forages either in the field or in
storage as hay or silage (Lancey, 1991). The limiting factor for fungi growth in hay is
moisture, in silage pH (Kalac, Woolford, 1982). At present nearly 400 mycotoxins
produced by a wide spectrum of fungal pathogens are described but the occurrence of
only the most frequent and harmful ones is monitored on a regular basis (Lew et al.
2001). Fungi and their mycotoxins identified in feeds (silage) may occur either through
their deleterious effects on nutrient and hygienic quality (Tapia et al. 2005).
Aflatoxins are a family of extremely toxic, mutagenic and carcinogenic
compounds produced by Aspergillus flavus and Aspergillus parasiticus (Deiner et al.
1987). Zearalenone is estrogenic metabolite of several species of Fusarium.
Zearalenone has been reported to occur in corn, other grains and silage in many areas
of the world (Hagler et al. 1984). Trichothecenes, T-2 toxin and deoxynivalenol too, are
commonly found in agricultural commodities (Desjardins et al. 1993). Fumonisins has
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