Urinary zearalenone measured with ELISA as a biomarker of zearalenone exposure in pigs.

The suitability to assess zearalenone (ZEA) exposure in pigs of a commercial ELISA kit for ZEA analysis in urine was tested. A daily dose of 0, 5, 10, 20 and 40 µg synthetic ZEA per kilogram BW was administered via the feed to four gilts per dose group, and after 3 and after 7 days of ZEA intake, urine samples were assayed with the ELISA which has a relative cross-reactivity of 42% with α-zearalenol. The concentration of urinary ZEA equivalents (ZEA plus 42% of α-zearalenol present) did not differ between day 4 and day 8 (P = 0.50) within each dose group. The urinary ZEA equivalent/creatinine ratio was tightly correlated with ZEA intake (r = 0.95). The urinary ZEA equivalent/creatinine values at 0 and 40 µg/kg BW were distinctly different from those of the intermediate dose levels, whereas there was some overlapping of the individual values at the dose levels 5, 10 and 20 µg/kg BW. The urinary ZEA equivalent/creatinine ratio can be used as a biomarker for ZEA exposure in pigs provided that urine samples of several animals receiving the same diet are assayed, either separately or after pooling.

Fertility of sows exposed to zearalenone and deoxynivalenol-a case report.

In a commercial breeding herd of 140 sows, the introduction of a lot of ensiled corn cob mix (CCM) contaminated with 6-11 mg deoxynivalenol and 3-5 mg zearalenone per kg dry matter (DM) into the ration of the pregnant sows and of the gilts immediately decreased its palatability. The contaminated CCM in the ration was reduced from 60% to 40% in the DM after 1 month and was completely eliminated after a further 2.5 months. The reproductive performance data of the herd during the 5 months after the introduction of the contaminated CCM (e.g. 88% non-return rate, 10.2 weaned piglets per litter, no abortion, no pseudopregnancy) were similar to the data obtained for the same period of the previous year. The high mycotoxin exposure thus had no obvious negative effects on fertility.

Fusarium toxins in cereals grown in Switzerland.

770 cereal samples of Swiss origin which were collected in various feed mills and cereal collection centres in the years 2000 - 2002 were assayed for Deoxynivalenol (DON) and zearalenone (ZEA). 137 samples were also assayed for T-2 toxin. The prevalence of DON and ZEA contamination was higher in cereals harvested in the rainy summer 2002 than in the previous years. T-2 toxin levels exceeding 100 µg/kg were found only in three oats samples. High levels ofFusarium toxins do not frequently occur in Swiss cereals.

Identification and semiquantitative estimation of antibiotics added to complete feeds, premixes, and concentrates.

Classical microbiological methods for determining antimicrobial compounds in feeds are nonspecific. Thus, there is a need to identify biological activity, and bioautography is used for this purpose. A routine method for detecting the following antimicrobial substances in feeds is described: avilamycin, avoparcin, Zn-bacitracin, erythromycin, flavomycin, furazolidone, lasalocid, monensin, narasin, penicillin, salinomycin, spiramycin, tetracyclines, tylosin, and virginiamycin. Carbadox can be detected by UV light examination of the plates prior to bioautography. Semiquantitative estimations of antibiotic content are compared with quantitative determinations of the above mentioned substances in feeds, except erythromycin, penicillin, and tetracyclines. Detection limits range from 0.1 mg/kg (chlortetracycline) to 20 mg/kg (lasalocid). The method involves agar diffusion of buffered samples, a neutral extraction of polyether antibiotics followed by thin-layer chromatography (TLC), and an acid extraction for other antibiotics followed by TLC. Five test bacteria were used for the main detection by agar diffusion: Micrococcus luteus ATCC 9341, Staphylococcus aureus ATCC 6538P, Corynebacterium xerosis NCTC 9755, Bacillus cereus ATCC 11778, and B. subtilis ATCC 6633. Identification after TLC was achieved by bioautography with the most sensitive microorganism(s). This method allows one laboratory technician to analyze up to 30 feed samples within 2.5 working days, provided that feeds of the same category are analyzed in the same run, and that labels of additives are available. Qualitative and semiquantitative information are valuable when performing a quantitative antibiotic determination and it provides proof that the activity determined is due to the tested substance. This last feature is essential from the perspective of quality assurance of results.