Effects of Fusarium toxin-contaminated wheat and feed intake level on the biotransformation and carry-over of deoxynivalenol in dairy cows
An experiment was carried out to examine the effects of feeding Fusarium toxin-contaminated wheat (8.21mg deoxynivalenol (DON) and 0.09mg zearalenone (ZON) per kg dry matter) at different feed intake levels on the biotransformation and carry-over of DON in dairy cows. For this purpose, 14 ruminal and duodenal fistulated dairy cows were fed a diet containing 60% concentrate with a wheat portion of 55% ( Fusarium toxin-contaminated wheat (mycotoxin period) or control wheat (control period)) and the ration was completed with maize- and grass silage (50:50) on a dry matter basis. Daily DON intakes ranged from 16.6 to 75.6mg in the mycotoxin period at dry matter intakes of 5.6–20.5kg. DON was almost completely biotransformed to de-epoxy DON (94–99%) independent of the DON/feed intake, and the flow of DON and de-epoxy DON at the duodenum related to DON intake ranged from 12 to 77% when the Fusarium toxin-contaminated wheat was fed. In the serum samples, de-epoxy DON was detected in the range of 4–28ngml −1 in the mycotoxin period, while concentrations of DON were all below the detection limit. The daily excretion of DON and de-epoxy DON in the milk of cows fed the contaminated wheat varied between 1 and 10µg and between 14 and 104µg, respectively. The total carry-over rates as the ratio between the daily excretion of DON and de-epoxy DON into milk and DON intake were in the ranges of 0.0001–0.0002 and 0.0004–0.0024, respectively. Total carry-over rates of DON as DON and de-epoxy DON into the milk increased significantly with increasing milk yield. In the urine samples, de-epoxy DON was the predominant substance as compared with DON with a portion of the total DON plus de-epoxy DON concentration to 96% when the Fusarium toxin-contaminated wheat was fed, whereas the total residues of DON plus de-epoxy DON in faeces ranged between 2 and 18% of DON intake in the mycotoxin period. The degree of glucuronidation of de-epoxy DON was found to be approximately 100% in serum. From 33 to 80% of DON and from 73 to 92% of de-epoxy DON, and from 21 to 92% of DON and from 86 to 100% of de-epoxy DON were glucuronidated in the milk and urine, respectively. It is concluded that DON is very rapidly biotransformed to de-epoxy DON in the rumen and only negligible amounts of DON and de-epoxy DON were transmitted into the milk within the range of 5.6–20.5kgday −1 dry matter intake and milk yields (fat corrected milk) between 10 and 42kgday −1 .
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level of feed intake;
Document Type: Research Article
Federal Agricultural Research Centre (FAL), Institute of Animal Nutrition, Bundesallee 50, Braunschweig, D-38116, Germany
Laboratory for Food and Residue Analyses (ARO), National Institute for Public Health and the Environment (RIVM), EU Community Reference Laboratory for Residues (CRL), PO Box 1, NL-3720 BA Bilthoven, The Netherlands
Institute of Animal Nutrition, Hohenheim University, Emil-Wolff-Str. 10, Stuttgart, D-70599, Germany
Department of Veterinary Public Health and Food Sciences/Institute of Nutrition, University of Veterinary Medicine, Veterinarplatz 1, Vienna, A-1210, Austria
October 1, 2006
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