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 (8.21 mg deoxynivalenol (DON) and 0.09 mg 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 75.6 mg in the mycotoxin period at dry matter intakes of 5.6-20.5 kg. 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 4-28 ng ml-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 10 microg and between 14 and 104 microg, 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 5.6-20.5 kg day-1 dry matter intake and milk yields (fat corrected milk) between 10 and 42 kg day-1.
Seeling
K
K
Federal Agricultural Research Centre (FAL), Institute of Animal Nutrition, Bundesallee 50, Braunschweig, D-38116, Germany. karen.seeling@fal.de
Dänicke
S
S
Valenta
H
H
Van Egmond
H P
HP
Schothorst
R C
RC
Jekel
A A
AA
Lebzien
P
P
Schollenberger
M
M
Razzazi-Fazeli
E
E
Flachowsky
G
G
D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001711:Biotransformation; D002417:Cattle / Q000378:metabolism*; D004386:Duodenum / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D005260:Female; D005504:Food Analysis / Q000379:methods; D005506:Food Contamination / Q000032:analysis*; D005670:Fusarium; D008892:Milk / Q000737:chemistry; D014255:Trichothecenes / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics*; D014908:Triticum / Q000737:chemistry*
D014255:Trichothecenes; C007262:deoxynivalenol