Monitoring of natural zearalenone contamination in feeds of cattle herds, with special focus on the effect on reproductive efficacy.

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The aims of the first study were (1) to investigate the efficacy of measuring bovine urinary zearalenone (ZEN) concentrations by using a commercially available ELISA method in cattle kept under different feeding conditions to monitor the natural contamination of feeds at the farm level, and (2) to investigate the effects of supplementation of a mycotoxin adsorbent (MA) product in the feed based on urinary ZEN concentration. The findings indicate the usefulness of measuring concentrations of urinary ZEN and its metabolites not only for monitoring the natural ZEN contamination of cattle feed at the farm level but also for in vivo evaluation of MA function after supplementing feeds with MA.Zearalenone (ZEN) and its metabolites are important nonsteroidal estrogenic mycotoxins that cause reproductive disorders in domestic animals, especially pigs. The aim of the second study were to simultaneously detect ZEN and its metabolites α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL) in porcine follic … More ular fluid (FF) by liquid chromatography-tandem mass spectrometry. ZEN and α-ZOL, but not β-ZOL, were detected in all pooled FF samples collected from coexisting follicles (diameter >6mm) within 10 ovaries. Furthermore, ZEN and α-ZOL were detected in samples pretreated with β-glucuronidase/arylsulfatase, but not in those left untreated, suggesting that the FF samples contained glucuronide-conjugated forms of the mycotoxins that may be less harmful to porcine oocytes due to glucuronidation affecting the receptor binding. Nonetheless, the effects of the glucuronide-conjugated forms should be studied, both in vitro and in vivo. Additionally, the influence of acute exposure to zearalenone (ZEN) on porcine oocyte maturation, fertilization, or sperm penetration ability during both in vitro maturation and fertilization was evaluated. First, oocytes were cultured in ZEN-containing (0-1000μg/l) maturation medium and then fertilized. Second, oocytes maturing in vitro without ZEN were fertilized in ZEN-containing fertilization medium. The maturation rates of oocytes and penetration ability of sperm decreased significantly in the presence of 1000μg/l of ZEN. However, neither increases in the rates of degeneration and DNA fragmentation of oocytes nor reductions in normal and polyspermic fertilization were observed. ZEN did not affect the sperm penetration rates, however, 1000μg/l ZEN had positive effects on normal and polyspermic fertilization rates. Therefore, it can be suggested that an acute exposure of porcine oocytes during maturation, and oocytes and sperm during fertilization to ZEN up to 1000μg/l may not affect the fertility of the oocytes. Less