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Purves RW, Souster K, West M, Huda AM, Fisher CME, Belford MW, Shurmer BO. Improved Thyreostatic Drug Detection in Animal Tissues Using Liquid Chromatography-High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:4785-4791. [PMID: 35060701 DOI: 10.1021/acs.jafc.1c06937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Thyreostatic drugs (thyreostats) interfere with thyroid function and have been used illegally in animals slaughtered for food. Thyreostat use leads to poorer quality meat, and the drug residues can cause adverse effects in humans. These drugs, with the exception of thiouracil, do not occur naturally and require sensitive methodologies for their detection in animal tissues. Because thyreostats are low-molecular-weight polar analytes, liquid chromatography-mass spectrometry (LC-MS) is typically used for detection and, in particular, triple quadrupole mass spectrometry with selective reaction monitoring (i.e., LC-SRM). However, LC-SRM thyreostat methods suffer from chemical background noise and endogenous interferences arising from the complex tissue matrix. An improved high-field asymmetric waveform ion mobility spectrometry interface (FAIMS Pro), which separates ions based on differential ion mobility, was combined with LC-SRM to minimize these interferences. Using the same samples and conditions, LC-FAIMS-SRM showed improvements in the signal-to-noise ratio (S/N) of up to 50 times compared with our validated LC-SRM method. In addition, wider linear ranges, including substantial improvements in the lower limit of quantification (approximately an order of magnitude for tapazole and methylthiouracil), were observed with LC-FAIMS-SRM.
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Affiliation(s)
- Randy W Purves
- Centre for Veterinary Drug Residues, Canadian Food Inspection Agency, Saskatoon, Saskatchewan S7N 2R3, Canada
| | - Kim Souster
- Centre for Veterinary Drug Residues, Canadian Food Inspection Agency, Saskatoon, Saskatchewan S7N 2R3, Canada
| | - Michelle West
- Centre for Veterinary Drug Residues, Canadian Food Inspection Agency, Saskatoon, Saskatchewan S7N 2R3, Canada
| | - Azhar M Huda
- Centre for Veterinary Drug Residues, Canadian Food Inspection Agency, Saskatoon, Saskatchewan S7N 2R3, Canada
| | - Caleb M E Fisher
- Centre for Veterinary Drug Residues, Canadian Food Inspection Agency, Saskatoon, Saskatchewan S7N 2R3, Canada
| | - Michael W Belford
- Thermo Fisher Scientific, 355 River Oaks Parkway, San Jose, California 95134, United States
| | - Bryn O Shurmer
- Centre for Veterinary Drug Residues, Canadian Food Inspection Agency, Saskatoon, Saskatchewan S7N 2R3, Canada
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Blokland MH, van Tricht FE, Groot MJ, Van Ginkel LA, Sterk SS. Discrimination between the exogenous and endogenous origin of thiouracil in farm animals, the final chapter? Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2021; 38:2077-2090. [PMID: 34477489 DOI: 10.1080/19440049.2021.1967463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
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 µg/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 µg/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 µg/L and in some cases above 30 µg/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 µg/L and for porcine urine samples at 30 µg/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.
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Affiliation(s)
- Marco H Blokland
- Growth Promoters, Wageningen Food Safety Research (WFSR), Part of Wageningen University & Research, European Union Reference Laboratory for Residues, Wageningen, The Netherlands
| | - Frederike E van Tricht
- Growth Promoters, Wageningen Food Safety Research (WFSR), Part of Wageningen University & Research, European Union Reference Laboratory for Residues, Wageningen, The Netherlands
| | - Maria J Groot
- Growth Promoters, Wageningen Food Safety Research (WFSR), Part of Wageningen University & Research, European Union Reference Laboratory for Residues, Wageningen, The Netherlands
| | - Leendert A Van Ginkel
- Growth Promoters, Wageningen Food Safety Research (WFSR), Part of Wageningen University & Research, European Union Reference Laboratory for Residues, Wageningen, The Netherlands
| | - Saskia S Sterk
- Growth Promoters, Wageningen Food Safety Research (WFSR), Part of Wageningen University & Research, European Union Reference Laboratory for Residues, Wageningen, The Netherlands
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Ji Z, Yu Y, Jin Q, Li G, Hu N, Zhou W, Suo Y, Sun Z, You J. Determination of naturally occurring thyreostats in bovine milk by high performance liquid chromatography combined with fluorescence detection. Microchem J 2019. [DOI: 10.1016/j.microc.2018.11.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Tölgyesi Á, Giri A, Barta E, McDonald TJ, Sharma VK. Determination of Thyreostats in Urine Using Supported Liquid Extraction and Mixed-Mode Cation-Exchange Solid-Phase Extraction: Screening and Confirmatory Methods. J Chromatogr Sci 2018; 56:858-866. [PMID: 29878072 DOI: 10.1093/chromsci/bmy054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 05/09/2018] [Indexed: 11/13/2022]
Abstract
The application of thyreostats in livestock has been banned in the European Union since 1981, but these drugs are currently in the focus due to the natural occurrence of thiouracil (TU). Studies have been published on TU contamination in urine samples of animal and human origins without any drug administration of it. This paper presents new analytical methods to analyze thyreostats to support the legislation on the recommended concentration (RC) levels of these drugs. Both screening and confirmatory methods are developed for analyzing thyreostats in porcine and bovine urines using a liquid chromatography-tandem mass spectrometry technique. The new methods include a chemical derivatization with 3-iodobenzyl bromide, followed by novel purification approaches using supported liquid extraction and mixed-mode cation-exchange solid-phase extraction (SPE) for screening and confirmatory purposes, respectively. The optimized derivatization in combination with the cation-exchange SPE gives high sensitivity and reducing matrix effect of the analysis. The methods are validated in accordance with the guidelines for the validation of screening methods and European Commission Decision 2002/657/EC. The confirmatory method is used in the national monitoring plan. The detected levels of TU in urine samples are below the currently applicable RC level (10 μg L-1).
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Affiliation(s)
- Ádám Tölgyesi
- National Food Chain Safety Office, Food and Feed Safety Directorate, Food Toxicological National Reference Laboratory, Mester utca 81, Budapest, Hungary
| | - Anupam Giri
- University of Liège, Chemistry Institute, Mass Spectrometry Laboratory, Organic & Biological Analytical Chemistry Group, allée du 6 aout, B6c, Liège, Belgium
| | - Eniko Barta
- Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szt. Gellért tér 4, Budapest, Hungary
| | - Thomas J McDonald
- Program for the Environment and Sustainability, Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, 212 Adriance Lab Road, 1266 TAMU, College Station, TX, USA
| | - Virender K Sharma
- Program for the Environment and Sustainability, Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, 212 Adriance Lab Road, 1266 TAMU, College Station, TX, USA
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Rocchi S, Caretti F, Mainero Rocca L, Pérez-Fernández V, Tomai P, Dal Bosco C, Curini R, Gentili A. Subcritical water extraction of thyreostats from bovine muscle followed by liquid chromatography-tandem mass spectrometry. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2018; 35:1472-1483. [PMID: 29843563 DOI: 10.1080/19440049.2018.1472393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Thyreostats can be used fraudulently to promote a rapid increase in weight of breeding animals at low cost. Their severe toxicological effects impose the development of reliable analytical methods to be used in monitoring plans. This work describes an alternative approach to isolate residues of thiouracil, methyl-thiouracil, propyl-thiouracil, phenyl-thiouracil, tapazole and mercaptobenzimidazole from bovine muscle tissue. The developed procedure is based on the following three steps: i) matrix solid-phase dispersion with C18 for the preliminary sample preparation; ii) subcritical water extraction (SWE) at 160°C and 100 bar; iii) clean-up on an Oasis HLB cartridge. The quantitative determination was performed by LC-MS/MS in dual polarity ionization by using internal standardization. The SWE-LC-MS/MS method was validated according to the identification criteria of the Commission decision 2002/657/EC. The relative recoveries ranged from 72 to 97%; within-lab reproducibility was less than 18%. The decision limit and the detection capability of all analytes were below the recommended concentration, set at 10 µg kg-1, but the validation results demonstrated that this method could only be applied for screening of thiouracil and methyl-thiouracil. Besides the analytical advantages related to the use of water as solvent extraction, the procedure allowed significant removal of lipids, whose detrimental effects on instrumentation and MS sensitivity are well-known.
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Affiliation(s)
- Silvia Rocchi
- a Department of Chemistry , "La Sapienza" University , Rome , Italy
| | - Fulvia Caretti
- a Department of Chemistry , "La Sapienza" University , Rome , Italy
| | | | | | - Pierpaolo Tomai
- a Department of Chemistry , "La Sapienza" University , Rome , Italy
| | - Chiara Dal Bosco
- a Department of Chemistry , "La Sapienza" University , Rome , Italy
| | - Roberta Curini
- a Department of Chemistry , "La Sapienza" University , Rome , Italy
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6
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Van Meulebroek L, Wauters J, Pomian B, Vanden Bussche J, Delahaut P, Fichant E, Vanhaecke L. Discovery of urinary biomarkers to discriminate between exogenous and semi-endogenous thiouracil in cattle: A parallel-like randomized design. PLoS One 2018; 13:e0195351. [PMID: 29649241 PMCID: PMC5896977 DOI: 10.1371/journal.pone.0195351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/20/2018] [Indexed: 12/22/2022] Open
Abstract
In the European Union, the use of thyreostats for animal fattening purposes has been banned and monitoring plans have been established to detect potential abuse. However, this is not always straightforward as thyreostats such as thiouracil may also have a semi-endogenous origin. Therefore, this study aimed at defining urinary metabolites, which may aid in defining the origin of detected thiouracil. Hereto, a parallel-like randomized in vivo study was conducted in which calves (n = 8) and cows (n = 8) were subjected to either a control treatment, rapeseed-enriched diet to induce semi-endogenous formation, or thiouracil treatment. Urine samples (n = 330) were assessed through metabolic fingerprinting, employing liquid-chromatography and Q-ExactiveTM Orbitrap mass spectrometry. Urinary fingerprints comprised up to 40,000 features whereby multivariate discriminant analysis was able to point out significant metabolome differences between treatments (Q2(Y) ≥ 0.873). Using the validated models, a total of twelve metabolites (including thiouracil) were assigned marker potential. Combining these markers into age-dependent biomarker panels rendered a tool by which sample classification could be improved in comparison with thiouracil-based thresholds, and this during on-going thiouracil treatment (specificities ≥ 95.2% and sensitivities ≥ 85.7%), post-treatment (sensitivities ≥ 80% for ≥ 24 h after last administration), and simulated low-dose thiouracil treatment (exogenous thiouracil below 30 ng μL-1). Moreover, the metabolic relevance of revealed markers was supported by the suggested identities, for which a structural link with thiouracil could be determined in most cases. The proposed biomarker panels may contribute to a more justified decision-making in monitoring thiouracil abuse.
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Affiliation(s)
- Lieven Van Meulebroek
- Laboratory of Chemical Analysis, Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, Belgium
- * E-mail:
| | - Jella Wauters
- Laboratory of Chemical Analysis, Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, Belgium
| | - Beata Pomian
- Laboratory of Chemical Analysis, Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, Belgium
| | - Julie Vanden Bussche
- Laboratory of Chemical Analysis, Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, Belgium
| | | | - Eric Fichant
- Health Department, CER Groupe, Rue Point du Jour, Marloie, Belgium
| | - Lynn Vanhaecke
- Laboratory of Chemical Analysis, Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, Belgium
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7
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Wozniak B, Matraszek-Zuchowska I, Witek S, Zmudzki J, Posyniak A. The effect of diet enriched with rapeseed meal on endogenous thiouracil contents in urine and milk of cattle. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2018; 35:892-899. [DOI: 10.1080/19440049.2017.1416181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Barbara Wozniak
- Department of Pharmacology and Toxicology, National Veterinary Research Institute, Pulawy, Poland
| | | | - Sebastian Witek
- Department of Pharmacology and Toxicology, National Veterinary Research Institute, Pulawy, Poland
| | - Jan Zmudzki
- Department of Pharmacology and Toxicology, National Veterinary Research Institute, Pulawy, Poland
| | - Andrzej Posyniak
- Department of Pharmacology and Toxicology, National Veterinary Research Institute, Pulawy, Poland
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8
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Wauters J, Van Meulebroek L, Fichant E, Delahaut P, Vanhaecke L. Discrimination between Synthetically Administered and Endogenous Thiouracil Based on Monitoring of Urine, Muscle, and Thyroid Tissue: An in Vivo Study in Young and Adult Bovines. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:6231-6239. [PMID: 28692258 DOI: 10.1021/acs.jafc.7b01920] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Thiouracil (TU), synthesized for its thyroid-regulating capacities and alternatively misused in livestock for its weight-gaining effects, is acknowledged to have an endogenous origin. Discrimination between low-level abuse and endogenous occurrence is challenging and unexplored in an experimental setting. Therefore, cows (n = 16) and calves (n = 18) were subjected to a rapeseed-supplemented diet or treated with synthetic TU. Significant higher urinary TU levels were recorded after TU administration (<CCα, 15 642 μg L-1) compared to rapeseed supplementation (<CCα, 65.8 μg L-1), however, with overlapping values. TU was not detected in the edible meat; however, concentrations between the CCα and 10 μg kg-1 were noted in thyroid tissue of calves and cows following rapeseed supplementation. The latter concentrations were significantly higher in thyroid tissue of calves (22.9-41.8 μg kg-1) and cows (16.9-36.7 μg kg-1) after synthetic TU administration. These results strongly point toward thyroid analysis as a discriminatory tool.
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Affiliation(s)
- J Wauters
- Ghent University , Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, 9820 Merelbeke, Belgium
| | - L Van Meulebroek
- Ghent University , Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, 9820 Merelbeke, Belgium
| | - E Fichant
- CER Groupe , Health Department, 6900 Marloie, Belgium
| | - P Delahaut
- CER Groupe , Health Department, 6900 Marloie, Belgium
| | - L Vanhaecke
- Ghent University , Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, 9820 Merelbeke, Belgium
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9
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Gentili A, De Pratti V, Caretti F, Pérez-Fernández V, Tomai P, Curini R, Mainero Rocca L. Residue analysis of thyreostats in baby foods via matrix solid phase dispersion and liquid chromatography – dual-polarity electrospray – tandem mass spectrometry. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2016; 33:1793-1802. [DOI: 10.1080/19440049.2016.1241899] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Alessandra Gentili
- Department of Chemistry, Faculty of Mathematical, Physical and Natural Sciences, ‘Sapienza’ University of Rome, Rome, Italy
| | - Valeria De Pratti
- Department of Chemistry, Faculty of Mathematical, Physical and Natural Sciences, ‘Sapienza’ University of Rome, Rome, Italy
| | - Fulvia Caretti
- Department of Chemistry, Faculty of Mathematical, Physical and Natural Sciences, ‘Sapienza’ University of Rome, Rome, Italy
| | - Virginia Pérez-Fernández
- Department of Chemistry, Faculty of Mathematical, Physical and Natural Sciences, ‘Sapienza’ University of Rome, Rome, Italy
| | - Pierpaolo Tomai
- Department of Chemistry, Faculty of Mathematical, Physical and Natural Sciences, ‘Sapienza’ University of Rome, Rome, Italy
| | - Roberta Curini
- Department of Chemistry, Faculty of Mathematical, Physical and Natural Sciences, ‘Sapienza’ University of Rome, Rome, Italy
| | - Lucia Mainero Rocca
- Department of Chemistry, Faculty of Mathematical, Physical and Natural Sciences, ‘Sapienza’ University of Rome, Rome, Italy
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Chiesa LM, Labella GF, Pasquale E, Panseri S, Pavlovic R, Arioli F. Determination of Thyreostats in Bovine Urine and Thyroid Glands by HPLC–MS/MS. Chromatographia 2016. [DOI: 10.1007/s10337-016-3068-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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11
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Wauters J, Vanden Bussche J, Bizec BL, Kiebooms JAL, Dervilly-Pinel G, Prevost S, Wozniak B, Sterk SS, Grønningen D, Kennedy DG, Russell S, Delahaut P, Vanhaecke L. Toward a new European threshold to discriminate illegally administered from naturally occurring thiouracil in livestock. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:1339-1346. [PMID: 25611753 DOI: 10.1021/jf504475f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Thiouracil is a thyrostat inhibiting the thyroid function, resulting in fraudulent weight gain if applied in the fattening of livestock. The latter abuse is strictly forbidden and monitored in the European Union. Recently, endogenous sources of thiouracil were identified after frequently monitoring low-level thiouracil positive urine samples and a "recommend concentration" (RC) of 10 μg/L was suggested by the EURL to facilitate decision-making. However, the systematic occurrence of urine samples exceeding the RC led to demands for international surveys defining an epidemiologic threshold. Therefore, six European member states (France, Poland, The Netherlands, United Kingdom, Norway, and Belgium) have shared their official thiouracil data (2010-2012) collected from bovines, porcines, and small livestock with 95 and 99% percentiles of 8.1 and 18.2 μg/L for bovines (n = 3894); 7.4 and 13.5 μg/L for porcines (n = 654); and 7.4 μg/L (95% only) for small livestock (n = 85), respectively. Bovine percentiles decreased with the animal age (nonadults had significantly higher levels for bovines), and higher levels were observed in male bovines compared to female bovines.
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Affiliation(s)
- Jella Wauters
- Ghent University , Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, Salisburylaan 133, 9820 Merelbeke, Belgium
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12
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Validation of a quantitative method using liquid chromatography coupled to multiple mass spectrometry for thiouracil in feedstuffs used in animal husbandry. Anal Bioanal Chem 2014; 407:4373-84. [DOI: 10.1007/s00216-014-8347-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 11/10/2014] [Accepted: 11/14/2014] [Indexed: 10/24/2022]
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Thiouracil-Forming Bacteria Identified and Characterized upon Porcine In Vitro Digestion of Brassicaceae Feed. Appl Environ Microbiol 2014; 80:7433-42. [PMID: 25261511 DOI: 10.1128/aem.02370-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 09/19/2014] [Indexed: 11/20/2022] Open
Abstract
In recent years, the frequent detection of the banned thyreostat thiouracil (TU) in livestock urine has been related to endogenous TU formation following digestion of glucosinolate-rich Brassicaceae crops. Recently, it was demonstrated that, upon in vitro digestion of Brassicaceae, fecal bacteria induce TU detection in livestock (porcine livestock > bovines). Therefore, the present study was intended to isolate and identify bacteria involved in this intestinal TU formation upon Brassicaceae digestion and to gain more insight into the underlying mechanism in porcine livestock. Twenty porcine fecal inocula (gilts and multiparous sows) were assessed through static in vitro colonic-digestion simulations with rapeseed. After derivatization and extraction of the fecal suspensions, TU was analyzed using liquid chromatography-tandem mass spectrometry (LC-MS(2)). On average, lower TU concentrations were observed in fecal colonic simulations in gilts (8.35 ng g(-1) rapeseed ± 3.42 [mean ± standard deviation]) than in multiparous sows (52.63 ng g(-1) ± 16.17), which correlates with maturation of the gut microbial population with age. Further exploration of the mechanism showed cell-dependent activity of the microbial conversion and sustained TU-forming activity after subjection of the fecal inoculum to moderate heat over a time span of up to 30 min. Finally, nine TU-producing bacterial species were successfully isolated and identified by a combination of biochemical and molecular techniques as Escherichia coli (n = 5), Lactobacillus reuteri (n = 2), Enterococcus faecium (n = 1), and Salmonella enterica subsp. arizonae (n = 1). This report demonstrates that endogenous formation of TU is Brassicaceae induced and occurs under colonic conditions most likely through myrosinase-like enzyme activity expressed by different common intestinal bacterial species.
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Lega F, Contiero L, Biancotto G, Angeletti R. Determination of thyreostats in muscle and thyroid tissues by QuEChERS extraction and ultra-performance liquid chromatography tandem mass spectrometry. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2013; 30:949-57. [DOI: 10.1080/19440049.2013.780212] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Kiebooms JAL, Vanden Bussche J, Hemeryck LY, Fievez V, Vanhaecke L. Intestinal microbiota contribute to the endogenous formation of thiouracil in livestock. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:7769-7776. [PMID: 22834937 DOI: 10.1021/jf3017145] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In recent years, the frequent detection of the banned substance thiouracil (TU) in livestock urine has been related to its endogenous formation following consumption of glucosinolate-rich Brassicaceae crops. Besides, TU residues have been recovered in these crops upon plant-derived myrosinase hydrolysis. Through in vitro bovine and porcine static digestive simulations, the influence of gastrointestinal digestion of Brassicaceae-derived matrixes on TU formation was assessed. Following derivatization and LC-MS(2) analysis, TU was detected in colonic suspensions with traditional rapeseed, coarse colza "00" meal, cauliflower, and broccoli ranging from 3.47 to 30.96 μg kg(-1) (bovine) and from 3.55 to 26.34 μg kg(-1) (porcine). In stomach and small intestinal fluids, TU remained unfound, whereas upon rumen simulation TU was detected for coarse colza "00" meal (4.43 μg kg(-1)) and grounded traditional rapeseed (0.35 μg kg(-1)). The origin of this detection was investigated through filter-sterilizing and autoclaving the fecal inoculum causing a significant decrease in TU concentration, thereby reinforcing the possibility of an active bacterial involvement, which however was characterized with a high interanimal variation. In conclusion, these results support the previously proven endogenous origin of TU and acknowledge the active role of the gastrointestinal bacteria in TU formation, through production of an extracellular component.
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Affiliation(s)
- Julie A L Kiebooms
- Faculty of Veterinary Medicine, Department of Veterinary, Public Health and Food Safety, Ghent University, Merelbeke, Belgium
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