Joint International Conference on Long-term Experiments ...

een shown to cause leucoencephalomalacia in horses (Marasas et al. 1988), pulmonary
edema in swine (Harrison et al. 1990) and hepatoxicity in rats (Geldebrom et al. 1991).
Unlike foodstuffs, ultimate concentrations of individual mycotoxins are not for
individual categories of animals and feeds in many European countries. Therefore
detected results were compared to recommended limits published in the United States
of America. The critical concentration of zearalenone in all feeds and categories of
animals is 0.5 mg.kg 1 , the limiting concentration of T-2 toxin is the same. The critical
concentration of fumonisin is 5 mg.kg -1 . The limiting concentration of deoxynivalenol
is specific for cattle 10 mg.kg -1 , the critical amount of deoxynivalenol is 5 mg.kg -1 for
pigs.
The intention of the present experiment was to establish mycotoxins contamination
in fresh forage and silage of alfalfa.
MATERIAL AND METHODS
Second cut alfalfa (Medicago sativa) was harvested at the blooming stage, variety
Palava. After wilting (6 hours), alfalfa was chopper by chopper harvester to 15 mm
particle length. Wilted matter of alfalfa was conserved (281.6 g.kg -1 of dry matter)
without additives in silage units (capacity 15 dm 3 ). Silage units were opened after two
months. Samples of fresh alfalfa and silage were analyzed for mycotoxin
contamination. Fresh matter and alfalfa silage were tested on a number of mycotoxin in
two replicates for each mycotoxin. The following mycotoxins were monitored:
zearalenone, deoxynivalenol 5/5, fumonisin, aflatoxin and ochratoxin. We used
immuno-enzymatic method for determination amounts of mycotoxins by ELISA reader
(Noack, Slovak Republic) with veratox tests (quantitative test). Principle of the test is
determination of concentration in extract of feedstuffs by spectrophotometric method
(650 nm). Before extraction, samples had to been homogenous. Extraction was
performed with distilled water (DON 5/5), 70% solution of methanol (V/V) for
fumonisin, zearelenone and aflatoxin or 50% solution of methanol (V/V) for ochratoxin
and T-2 toxin.
RESULTS AND DISCUSSION
Many different mycotoxins have been found to occur on forages either in the field, or in
storage as hay or silage (Lacey, 1991). Silage contained higher numbers of mycotoxins
in comparison to amounts of mycotoxins in fresh matter (Table 1). Content of
deoxynivalenol was range from 200 to 300 μg.kg -1 it was 100 μg.kg -1 in fresh matter.
The highest concentration of fumonisin was 71.9 μg.kg -1 . Fumonisin has been shown to
reduce milk production in dairy cattle at 100 mg.kg -1 (Diaz et al., 2000). We found
similar results of zearalenone like Nedělník and Moravcová (2006), range from 635.8 to
703.1 μg.kg -1 . In Slovak climatic conditions, mycotoxins (aflatoxin and ochratoxin)
have produced by storage fungi (Leibetseder, 1995). We found aflatoxin with toxic
mutagenic and carcinogenic characteristics (Deiner et al., 1987) range from 10.4 μg.kg -1
to 11.9 μg.kg -1 , lower than reported Kalac and Woolford (1982). The concentration of
ochratoxin was 12.5 μg.kg -1 in fresh matter, it was range from 8.2 to 14.5 μg.kg -1 in
silage.
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