Toxicokinetic study and oral bioavailability of deoxynivalenol in turkey poults, and comparative biotransformation between broilers and turkeys

The aim of present study was to reveal the toxicokinetic properties and absolute oral bioavailability of deoxynivalenol (DON) in turkey poults. Six turkey poults were administered this Fusarium mycotoxin per os and intravenously in a two-way cross-over design. Based on non-compartmental analysis, DON was absorbed rapidly (T-max = 0.57 h) but incomplete, as the oral bioavailability was only 20.9%. DON was rapidly eliminated as well, both after oral (T-1/2elimination (PO)=0.86 h) as well as intravenous (IV) (T-1/2elimination IV = 0.62 h) administration. Furthermore, semi-quantitative analysis using high-resolution mass spectrometry revealed that DON-3 alpha-sulphate is the major metabolite of DON in turkeys after IV as well as oral administration, with DON-3 alpha-sulphate/DON ratios between 1.3-12.6 and 32.4-140.8 after IV and oral administration, respectively. Glucuronidation of DON to DON-3 alpha-glucuronide is a minor pathway in turkey poults, with DON-3 alpha-glucuronide/DON ratios between 0.009-0.065 and 0.020-0.481 after IV and oral administration, respectively. Only trace amounts of other metabolites were found including 10-DON-sulphonate, de-epoxydeoxynivalenol and 10-de-epoxydeoxynivalenol-sulphonate. In addition, a similar two-way cross-over study was performed in three broiler chickens, in order to compare the biotransformation of DON in both poultry species. High-resolution mass spectrometry revealed that DON-3 alpha-sulphate was the major metabolite of DON in broiler chickens as well, with DON-3 alpha-sulphate/DON ratios between 243-453 and 1,365-29,624 after IV and oral administration, respectively. These ratios indicate that broiler chickens metabolise DON even more extensively to the sulphate conjugate compared to turkey poults. Only trace amounts of other metabolites were detected in broiler chickens. In conclusion, it can be stated that the toxicokinetic behaviour of DON in broiler chickens and turkey poults is comparable (low absolute oral bioavailability, rapid absorption and elimination, extensive biotransformation to DON-3 alpha-sulphate), however, relative differences in DON-3 alpha-sulphate/DON ratios exist between both species which might explain the hypothesised difference in sensitivity of both poultry species to DON.