Discrimination between the exogenous and endogenous origin of thiouracil in farm animals, the final chapter?
| Autor: | Marco Blokland, Frederike van Tricht, Leendert A. van Ginkel, M.J. Groot, Saskia S. Sterk |
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| Rok vydání: | 2021 |
| Předmět: |
endocrine system
Rapeseed Project- en Accountmanagement Swine Health Toxicology and Mutagenesis Metabolite Programme and Account Management Endogeny Urine Toxicology thyreostatic BU Dierbehandelingsmiddelen Thiouracil BU Veterinary Drugs chemistry.chemical_compound Animal science biomarker discovery Animals Volume concentration thiouracil VLAG mass spectrometry High concentration Team Animal Drugs 2 Food analysis Public Health Environmental and Occupational Health General Chemistry General Medicine Animal Feed chemistry Team Growth Promotors Animals Domestic Brassicaceae Cattle food contaminants Food Analysis Food Science Food contaminant |
| Zdroj: | Food Additives and Contaminants-Part A Chemistry, Analysis, Control, Exposure and Risk Assessment 38 (2021) 12 Food Additives and Contaminants-Part A Chemistry, Analysis, Control, Exposure and Risk Assessment, 38(12), 2077-2090 |
| ISSN: | 1944-0057 1944-0049 |
| Popis: | Thiouracil (2-thiouracil) is a thyreostatic compound that can be used as an illegal growth promoter. In bovine, porcine and other farm animals, low concentrations of thiouracil are detected in urine. There is much debate on which concentrations can be considered to originate from feed (���natural���) and which concentrations are caused by the illegal administration of thiouracil for growth-promoting purposes. Currently, a threshold value of 10 ��g/L in urine is applied. The threshold value is based on epidemiological data. Data on thiouracil from animals treated with thiouracil is scarce. We conducted a study whereby animals were fed with rapeseed, rapeseed with thiouracil, or regular feed with thiouracil (low and high concentration). It was determined that administration of thiouracil leads to concentrations higher than the current 10 ��g/L threshold of thiouracil and its metabolites in urine during treatment. Animals fed with rapeseed showed higher thiouracil concentrations than the control group, mostly above 10 ��g/L and in some cases above 30 ��g/L. In the discovery study, several biomarkers for thiouracil treatment were tentatively identified and confirmed with reference standards. One metabolite was identified as indicative for thiouracil abuse, namely 6-methyl-thiouracil. Another metabolite, 4-thiouracil, was indicative for endogenous formation and did not increase during 2-thiouracil treatment. 6-Methyl-thiouracil was not found in urine samples from the Dutch routine control programmes that contained (endogenous) 2-thiouracil above the threshold value. However, 4-thiouracil was found at high concentrations in the same samples when 2-thiouracil was present. This study���s overall conclusion is that the threshold value for thiouracil in bovine urine samples should be set at 10 ��g/L and for porcine urine samples at 30 ��g/L. Also, confirmation of 6-methyl-thiouracil and 4-thiouracil should be used as indicators for exogenous or endogenous origin in routine control monitoring programmes. |
| Databáze: | OpenAIRE |
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