Control of the illegal administration of natural steroid hormones in the plasma of bulls and heifers

New surveillance concepts in food safety in meat producing animals: the advantage of high throughput 'omics' technologies - A review

The misuse of anabolic hormones or illegal drugs is a ubiquitous problem in animal husbandry and in food safety. The ban on growth promotants in food producing animals in the European Union is well controlled. However, application regimens that are difficult to detect persist, including newly designed anabolic drugs and complex hormone cocktails. Therefore identification of molecular endogenous biomarkers which are based on the physiological response after the illicit treatment has become a focus of detection methods. The analysis of the ‘transcriptome’ has been shown to have promise to discover the misuse of anabolic drugs, by indirect detection of their pharmacological action in organs or selected tissues. Various studies have measured gene expression changes after illegal drug or hormone application. So-called transcriptomic biomarkers were quantified at the mRNA and/or microRNA level by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) technology or by more modern ‘omics’ and high throughput technologies including RNA-sequencing (RNA-Seq). With the addition of advanced bioinformatical approaches such as hierarchical clustering analysis or dynamic principal components analysis, a valid ‘biomarker signature’ can be established to discriminate between treated and untreated individuals. It has been shown in numerous animal and cell culture studies, that identification of treated animals is possible via our transcriptional biomarker approach. The high throughput sequencing approach is also capable of discovering new biomarker candidates and, in combination with quantitative RT-qPCR, validation and confirmation of biomarkers has been possible. These results from animal production and food safety studies demonstrate that analysis of the transcriptome has high potential as a new screening method using transcriptional ‘biomarker signatures’ based on the physiological response triggered by illegal substances.

Assessment of endogenous androgen levels in meat, liver and testis of Iranian native cross-breed male sheep and bull by gas chromatography-mass spectrometry

Androgenic steroids always exist in different animal tissues at trace level, with significant numbers of interfering compounds, which makes their determination difficult. To solve some of the problems in quantification of the natural steroids in those tissues, a new GC-MS method was developed in this study. By using a surrogate analyte approach, which was developed in the authors' previous studies, and extensive sample preparation procedure, which successfully eliminates many of the interfering compounds and resulting in a cleaner extract, accuracy, precision, sensitivity and selectivity of the method for the determination of steroids in complex matrices such as meat, liver and testis were improved. By aid of this method, the levels of androgens in different tissues of Iranian native cross-breed bulls and male sheep were determined. According to the results obtained in the present study, although the androgenic profile (contents and ratios of precursors and metabolites to the main hormones) is similar between the same tissues of both animals, the total androgenic content of each tissue is higher in the bull than the same tissue in male sheep. In addition, in both animals higher amount of androgens were found in liver in comparison with meat and testis.

Disturbance in sex-steroid serum profiles of cattle in response to exogenous estradiol: a screening approach to detect forbidden treatments

Estradiol benzoate (EB) has been one of the most widely used estrogenic agents in animal husbandry, as a way of exogenously introducing the natural hormone estradiol-17β into the animal organism. Estradiol was previously employed to induce anabolic effects or reproductive improvements in cattle. However, the employment of EB in European countries has been permanently forbidden by Directive 2008/97/EC to guarantee consumers' health. Despite this prohibition, the control of estradiol-17β and its esters continues to be a difficult task for residue-monitoring plans in European Communities because official analyses of natural thresholds for hormones in cattle have not yet been established, leading to a lack of confirmation for any exogenous administration of natural hormones. Several researchers have worked on excretion profiles of metabolites, variation in specific hormonal ratios and metabolomic fingerprints after hormonal treatments. This research focuses on the possible existence of disturbances in the serum profile of animals treated with EB in terms of steroid sex hormones (androgens, oestrogens and progestogens), by investigating the serum levels of several of these hormones. The serum samples were collected from three groups of cows: one treated with an intramuscular injection of EB, one treated with a combination of intravaginal EB and progesterone and a control (non-treated) group. The samples have been analysed by a validated high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method, and 17 natural hormones were identified and quantified. Subsequently, data from the serum profiles were submitted for statistic and multivariate analysis, and it was possible to observe a manifest variation between animal groups. The obtained results can help in the development of a viable screening tool for monitoring purposes in cattle.

Gas chromatography-mass spectrometry/mass spectrometry analysis to determine natural and post-administration levels of oestrogens in bovine serum and urine

A novel analytical approach has been developed and shown to be capable of detecting the isomers of oestradiol in the low ppt (pg mL(-1)) range in bovine serum and urine. Following extractive derivatisation the analytes were detected as their 3-pentafluorobenzoyl 17-trimethylsilyl ether derivatives by gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS), using electron capture negative ion chemical ionisation. The isomers of oestradiol were quantified in both blank and post-administration urine and serum samples, with a view to setting action/threshold levels for these compounds, to allow discrimination between normal samples and samples from animals treated with growth promoting ear implants. A non-parametric statistical assessment of the data resulted in proposed action levels (with a false positive probability of 1 in 1000) of 1.6 and 2.7 ng mL(-1) for 17alpha-oestradiol, in male and female urine, respectively, and 40 and 44 pg mL(-1) for 17beta-oestradiol, in male and female urine, respectively. An action level of 20 pg mL(-1) was proposed for 17alpha- and 17beta-oestradiol in male serum. In female serum the proposed action levels were 40 and 20 pg mL(-1) for 17alpha- and 17beta-oestradiol, respectively.

Natural sex steroids and their xenobiotic analogs in animal production: growth, carcass quality, pharmacokinetics, metabolism, mode of action, residues, methods, and epidemiology

Natural and xenobiotic compounds having sex-related actions have long been used for growth promotion and various changes in carcass quality in meat animals. The first compounds used were synthetic estrogens; however, later on a whole battery of compounds having androgenic, and progestogenic actions have also been involved. In surveying the effects of these compounds in meat-producing animals, it became clear that these drugs increase the growth rate of the treated animals and bring about changes in the carcass that are generally characterized by lower fat content and more lean mass. Extensive studies undertaken in various countries, including the European Economic Community (EEC), have shown that if used according to good husbandry practices, the meat from treated animals does not have excessive amounts of residues compared with the endogenous amount of steroid production in the animals in question and also in human beings. The banning of these compounds in the European community brought a new phenomenon of illegal or black market cocktails. These mixtures of anabolic steroids are injected into the body of the animals rather than implanted in the ears, which is the normal practice in countries where they have not yet been banned. Several screening and confirmatory methods are now available for monitoring programs. However, these programs need excessive resources in terms of manpower, funds, and proper legislation, which in underdeveloped countries is questionable, particularly in the absence of strong scientific evidence for the exercise.