The levels of zearalenone and its metabolites in plasma, urine and faeces of horses fed with naturally, Fusarium toxin-contaminated oats.

Concentration profile of zearalenone (ZON) and its metabolites in plasma, urine and faeces samples of horses fed with Fusarium toxin-contaminated oats is described. In plasma, ß-zearalenol (ß-ZOL) was detected at high levels on day 10 of the study (3.21-6.24 µg/l). ß-Zearalenol and α-zearalenol were the major metabolites in urine. Zearalenone, α-ZOL and ß-ZOL were predominantly found in faeces. Zearalanone could also be detected in urine (1.34-5.79 µg/l) and faeces (1 µg/kg). The degree of glucuronidation was established in all sample types, approximately 100% in urine and plasma. Low per cent of glucuronidation (4-15%) was found in faeces samples. The results indicate the main conversion of ZON into ß-ZOL in horse. This finding could explain why horse is not susceptible to ZON in comparison with swine which produce α-ZOL as a predominant metabolite.

Occurrence of deoxynivalenol (DON) and ochratoxin A (OTA) in dog foods.

The commercially available dog food samples (29 dry foods and 11 wet foods) were analysed for deoxynivalenol (DON) and ochratoxin A (OTA) using ELISA. All (100%) dry foods were contaminated with DON with various amount of the toxin (22-1837 µg/kg). In wet food 3 samples were found to be positive for DON in the range of 95-170 µg/kg. There were a few samples contaminated with OTA: 3 samples in dry foods (7-40 µg/kg) and 2 samples in wet foods (45 and 115 µg/kg).

Determination of zearalenone and its metabolites in urine, plasma and faeces of horses by HPLC-APCI-MS.

The paper describes a method for the sensitive and selective determination of zearalenone and its metabolites in urine, plasma and faeces of horses by high performance liquid chromatography and atmospheric pressure chemical ionisation (APCI) mass spectrometry (MS). While only one step sample clean-up by an immunoaffinity column (IAC) was sufficient for plasma samples, urine and faeces samples had to be prepared by a combination of a solid-phase extraction (SPE) and an immunoaffinity column. The method allows the simultaneous determination of zearalenone and all of its metabolites; alpha-zearalenol, beta-zearalenol, alpha-zearalanol, beta-zearalanol and zearalanone. Dideuterated zearalanone was used as internal standard for quantification and the study of the matrix effect. Recovery rates between 56 and slightly above 100% were achieved in urine samples, and more than 80% in plasma and faeces samples. The limits of detection ranged from 0.1-0.5 microg/l or microg/kg, the limits of quantification from 0.5-1.0 microg/l or microg/kg. The practical use of the method is demonstrated by the analysis of spiked and naturally contaminated urine, plasma and faeces of horses.