Abuse of anabolic agents in beef cattle: Could bile be a possible alternative matrix?

Porphyrin-based metal-organic frameworks enhanced electrochemiluminescence (ECL) by overcoming aggregation-caused quenching: A new ECL emitter for the detection of trenbolone

The development of new electrochemiluminescence (ECL) luminophores has become a hot research topic in the field of ECL. Metal-organic frameworks (MOFs) are widely used in ECL sensors due to their excellent ECL performance, high porosity, and abundant surface functional groups. In the work, we developed a cerium-based organic backbone as an ECL luminophor using 5,10,15,20-tetrakis(4-carboxyphenyl)-porphyrin (TCPP) as organic ligand for the detection of trenbolone (TRE). Importantly, the Ce-MOFs can effectively prevent the self-aggregation and self-quenching of TCPP, so that the ECL signal is amplified. To further improve the conductivity and antigen loading capacity of the Ce-MOFs, platinum nanosheets (Pt NPs) were modified at its surface (Pt NPs@MOFs). The Au-ZnO with good biocompatibility is used as the substrate material to load that antibody through the Au-NH2. Based on the above strategy, we constructed a competitive immunosensor to achieve a highly sensitive detection of TRE. Under suitable circumstances, it was discovered that the ECL sensor had a linear relationship with the logarithm of the TRE concentration, with a limit of detection (LOD) of 3.61 fg/mL (S/N = 3). This work provides direction for the application of organic luminescent porphyrins and their derivatives in ECL sensors.

Occurrence of resorcyclic acid lactones in porcine urine: discrimination between illegal use and contamination

Zeranol (α-zearalanol, α-ZAL), is a resorcyclic acid lactone (RAL). Its administration to farm animals to improve meat production has been prohibited in the European Union due to the potential risk to human health. However, it has been demonstrated that α-ZAL may be present in livestock animals due to Fusarium fungi that produce fusarium acid lactones contamination in feed. The fungi produce a small amount of zearalenone (ZEN), which is metabolized to zeranol. The potential endogenous origin of α-ZAL makes it difficult to correlate positive samples to a potential illicit treatment with α-ZAL. We present two experimental studies that investigated the origin of natural and synthetic RALs in porcine urine. Urine samples from pigs that were either fed with ZEN-contaminated feed or administered α-ZAL by injection were analyzed by liquid chromatography coupled to tandem mass spectrometry, with the method validated according to Commission Implementing Regulation (EU) 2021/808. The data show that although the concentration of α-ZAL in the ZEN feed-contaminated samples is significantly lower than in the illicit administration samples, α-ZAL can occur in porcine urine via natural metabolism. Additionally, the feasibility of using the ratio of forbidden/fusarium RALs in porcine urine as a reliable biomarker for illicit treatment with α-ZAL administration was evaluated for the first time. This study demonstrated that the obtained ratio in the contaminated ZEN feed study was close to 1, while in the illegally administered α-ZAL samples the ratio is always higher than 1 (up to 135). Therefore, this study proves that the ratio criteria (already used when a forbidden RAL is detected in bovine urine) may also be used for porcine urine.

Exploration of a Molecularly Imprinted Polymer (MIPs) as an Adsorbent for the Enrichment of Trenbolone in Water

The presence of endocrine disruptors in surface waters can have negative implications on wildlife and humans both directly and indirectly. A molecularly imprinted polymer (MIP) was explored for its potential to enhance the UV-Vis determination of trenbolone in water using solid-phase extraction (SPE). The synthesized MIP was studied using Fourier transform infrared spectra (FTIR) and scanning electron microscopy (SEM). Using the MIP resulted in a preconcentration and enrichment factor of 14 and 8, respectively. Trenbolone binding on the MIP was shown to follow a Langmuir adsorption and had a maximum adsorption capacity of 27.5 mg g−1. Interference studies showed that the MIP selectivity was not compromised by interferences in the sample. The MIP could be recycled three times before significant loss in analyte recovery.

Evaluation of public and animal health risks in case of a delayed post-mortem inspection in ungulates

The potential effects of a 24 or 72-h delay in post-mortem inspection (PMI) of ungulates on public health and monitoring of animal health and welfare was evaluated. The assessment used a survey of meat inspectors, expert opinion, literature search and a stochastic model for Salmonella detection sensitivity. Disease detection sensitivity at a delayed PMI is expected to reduce detection sensitivity to a variable extent, depending on the hazard and on the signs/lesions and organs involved. No reduction is expected for Trichinella detection in meat from susceptible animal species and any decrease in detection of transmissible spongiform encephalopathies (TSEs) will not exceed the current tolerance for fallen stock. A 24-h delay in PMI could result in a small reduction in sensitivity of detection for tuberculosis, echinococcosis and cysticercosis. A greater reduction is expected for the detection of pyaemia and Rift valley fever. For the detection of Salmonella, the median model estimates are a reduction of sensitivity of 66.5% (90% probability interval (PI) 0.08-99.75%) after 24-h delay and 94% (90% PI 0.83-100%) after 72-h delay of PMI. Laboratory testing for tuberculosis following a sampling delay of 24-72 h could result in no, or a moderate, decrease in detection depending on the method of confirmation used (PCR, culture, histopathology). For chemical contaminants, a delay in meat inspection of 24 or 72 h is expected to have no impact on the effectiveness of detection of persistent organic pollutants and metals. However, for certain pharmacologically active substances, there will be a reduced effectiveness to detect some of these substances due to potential degradation in the available matrices (tissues and organs) and the non-availability of specific preferred matrices of choice.

Veterinary growth promoters in cattle feedlot runoff: estrogenic activity and potential effects on the rat male reproductive system

The contribution of veterinary growth promoters (VGP) to the environmental burden of endocrine-disrupting chemicals (EDCs) is largely unknown. At cattle feedlots, the excrement of cattle may contain VGPs, which can contaminate aquatic systems and pose reproductive health risks. The study identifies VGPs used at cattle feedlots in South Africa and confirms associated estrogenic activity in feedlot runoff water. Using a rat model, we investigate the potential reproductive health effects and thyroid function of an environmentally relevant mixture of VGPs. Collected water samples had low levels of selected VGPs, and estrogenic activity was detected in the T47D-KBluc bioassay. Rats exposed to VGP had significant adverse effects on male reproductive health, including shortened anogenital distance, lowered sperm counts, disorganized seminiferous tubules, and thyroid parameters. In conclusion, VGP can contribute to complex environmental EDC mixtures and may adversely affect the reproductive and thyroid health of both humans and wildlife. The varied topography of individual cattle feedlots will govern the rate and extent of effluent runoff, thus continuous monitoring of VGPs in aquatic systems surrounding cattle feedlots is necessary.

LC-MS/MS method for the determination of hormones: Validation, application and health risk assessment in various bovine matrices

A new method, using liquid chromatography coupled to mass spectrometry (LC-MS/MS) for the detection of fourteen natural and synthetic hormones in muscles, was validated in other bovine matrices (liver, kidney, bile and hair) according to the Decision Commission 2002/657/EC. As result, this method demonstrates good linearity (R² > 0.99) as well as accuracy with coefficients of variation for repeatability and reproducibility lower than 23%. Moreover, the values of decision limit (CCα) and detection capability (CCβ) were determined indicating values ranging from 0.13 to 0.86 μg/kg and 0.25-1.72 μg/k for the majority of analytes. Recovery rate in the different matrices varied from 51.5 to 107%. Indeed, this method has been successfully applied to detect anabolic hormones in eighty-eight samples (muscle, liver, kidney, and bile) collected from different local slaughterhouses. Results showed that progesterone was found in 30 samples at concentrations ranging from 0.11 to 11.7 μg/kg, while testosterone was detected in 34 samples at concentrations ranging from 0.5 to 9.52 μg/kg. All bile samples contain epi-testosterone at concentration ranging from 0.89 to 280 μg/kg. These obtained data were used to calculate the estimated daily intake, hazard quotient and hazard index as exposure assessment.