Suitability of feathers as control matrix for antimicrobial treatments detection compared to muscle and liver of broilers

Residue depletion of enrofloxacin and flumequine in feathers of broilers based on quantitative UHPLC-MS/MS detection

To explore potential factors contributing to high fluoroquinolone resistance levels, it is essential to develop analytical methods capable of detecting residues and trace amounts of antibiotic use in broilers. The aim of the present study was to develop and in-house validate a sensitive UHPLC-MS/MS method capable of determining enrofloxacin (ENR) and flumequine (FLU) residues at slaughter age (day 45) when the animals were treated with these antimicrobials one day after hatching. Residue depletion of ENR and FLU in feathers was also assessed. Two experimental trials were performed, both consisting of 5 different treatment groups. In the first trial animals were treated with ENR and in the second one with FLU. The developed method was successfully validated and was found to be sensitive enough to detect residues of fluoroquinolones in the feathers up until slaughter age in all treatment groups. Average ENR concentration on day 45 was 10 ng g-1 feather after drinking water treatment, with all concentrations above the limit of quantification (LOQ) of 5 ng g-1 feather. For FLU average concentration on day 45 after drinking water administration was 4 ng g-1 feather, with an LOQ of 1 ng g-1 feather. Therefore, the method is suited for application to monitor fluoroquinolone use in broilers.

Transcriptomic analysis of the effects of tylosin on the protective immunity provided by the Mycoplasma gallisepticum vaccine Vaxsafe MG ts-304

The antimicrobial tylosin is commonly used to control mycoplasma infections, sometimes in combination with vaccination. However, the efficacy of a live mycoplasma vaccine, when combined with subsequent antimicrobial treatment, against the effects of subsequent infection with a virulent strain is unknown. This study employed differential gene expression analysis to evaluate the effects of tylosin on the protection provided by the live attenuated Vaxsafe MG ts-304 vaccine, which has been shown to be safe and to provide long-term protective immunity against infection with Mycoplasma gallisepticum. The transcriptional profiles of the tracheal mucosa revealed significantly enhanced inflammation, immune cell proliferation and adaptive immune responses in unvaccinated, untreated birds and in unvaccinated birds treated with tylosin 2 weeks after infection with virulent M. gallisepticum. These responses, indicative of the typical immune dysregulation caused by infection with M. gallisepticum, were less severe in the unvaccinated, tylosin-treated birds than in the unvaccinated, untreated birds. This was attributable to the effect of residual levels of tylosin in the tracheal mucosa on replication of virulent M. gallisepticum. These responses were not detected in vaccinated, tylosin-treated birds or in vaccinated, untreated birds after infection. The tracheal mucosal transcriptional profiles of these birds resembled those of unvaccinated, untreated, uninfected birds, suggesting a rapid and protective secondary immune response and effective vaccination. Overall, these results show that, although tylosin treatment reduced the duration of immunity, the initial protective immunity induced by Vaxsafe MG ts-304 lasted for at least 22 weeks after vaccination, even after the administration of tylosin for 16 weeks following vaccination.

Multiresidue Determination of 26 Quinolones in Poultry Feathers Using UPLC-MS/MS and Their Application in Residue Monitoring

As a non-traditional sample matrix, feather samples can be used to effectively monitor antibiotic addition and organismal residue levels in poultry feeding. Therefore, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to simultaneously determine the residue levels of 26 quinolones in poultry feathers. The feather samples were extracted by sonication with a 1% formic acid and acetonitrile mixture in a water bath at 50 °C for 30 min, purified by the adsorption of multiple matrix impurities, dried with nitrogen, redissolved, and analyzed by UPLC-MS/MS. The linearity, limit of detection (LOD), limit of quantification (LOQ), recovery and precision were calculated. The 26 antibiotics demonstrated good linearity in the linear range. The recoveries and coefficients of variation were 78.9-110% and <13.7% at standard spiked levels of 10, 100 and 200 μg/kg, respectively. The LOD and LOQ were 0.12-1.31 and 0.96-2.60 μg/kg, respectively. The method also successfully identified quinolone residues in 50 poultry feather samples. The results showed that quinolones can accumulate and stabilize for a certain period of time after transferring from the body to the feathers of poultry.

Risk to Public Health Regarding Doxycycline Residues in Chicken Claws

Doxycycline residues in claws may pose a potential risk to humans. A study with broiler chickens was performed to find the concentrations of doxycycline in claws after treatment. For the quantification of the antibiotic of interest in claws, an ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed. Doxycycline was detectable at 3043 μg/kg at sub-therapeutic treatment, 223 μg/kg after therapeutic doses, and 14 μg/kg after spray application on the last day of the experiment (day 22). Almost 70 days is required for the concentration of doxycycline to reach zero. The obtained results show that monitoring of doxycycline in claws should be implemented.

Development and validation of a highly effective analytical method for the evaluation of the exposure of migratory birds to antibiotics and their metabolites by faeces analysis

The widespread occurrence of antibiotics in the environment may exert a negative impact on wild organisms. In addition, they can become environmental reservoirs, through the ingestion of food or contaminated water, and vectors for antibiotic-resistant bacteria. This fact is even more important in migratory birds that can promote their dissemination across continents. In this work, a multiresidue analytical method suitable for the determination of five families of antibiotics and their main metabolites in waterbird faeces has been developed and validated. The target compounds include environmentally significant sulfonamides, macrolides, fluoroquinolones, tetracyclines and antifolates. Sample treatment involves ultrasound-assisted extraction with methanol and dispersive solid-phase extraction clean-up with C18. Analytical determination was carried out by liquid chromatography-tandem mass spectrometry. The most significant parameters affecting sample extraction and extract clean-up were optimised by means of experimental designs. Good linearity (R² > 0.994), accuracy (from 41 to 127%), precision (relative standard deviation lower than 24%) and limits of quantification (lower than 2 ng g^-1 (dry weight, dw)) were obtained for most of the compounds. The method was applied to the determination of the selected compounds in 27 faeces samples from three common migratory waterbird species. Nine antibiotics and three of their metabolites were detected in the analysed samples. Fluoroquinolones and macrolides were the antibiotics most frequently detected. The highest concentrations corresponded to norfloxacin (up to 199 ng g^-1 dw).

Determining a wide range of antibiotics and pesticides in poultry feathers using selective accelerated solvent extraction-liquid chromatography-mass spectrometry

This study established a detection method based on accelerated solvent extraction-liquid chromatography-mass spectrometry for determining residues of 3 chloramphenicols, 8 macrolides, 18 sulfonamides, 4 nitroimidazoles, 15 insecticides, and 22 fungicides in poultry feathers. The extraction solvent, methanol, was used for a static extraction time of 5 min, and repeated three times. Fifty milligrams of adsorbents C18/PSA (1 : 1, W/W) were added to the extraction cell to achieve simultaneous extraction and purification. The extraction efficiency of three solvents, methanol, acetonitrile and ethyl acetate, was investigated. An orthogonal experimental design was used to explore the optimal combination of extraction temperature, static extraction time, number of extraction cycles, and adsorbent ratio for accelerated solvent extraction. After the optimal ratio was determined, the dosage of adsorbents was optimized. The extracted sample solution was concentrated by blowing nitrogen, redissolved, passed through a 0.22 μm PTFE membrane filter, then injected for instrumental analysis. The validation results showed that the recovery of the proposed method was 60.4-107.6%, the limit of detection 0.2-3.0 μg kg^-1, and the limit of quantification 0.5-8.3 μg kg^-1. This quantitative multi-residue detection method was able to determine the residues of 70 target compounds in poultry feathers.

Biomass porous carbon as the active site to enhance photodegradation of oxytetracycline on mesoporous g-C3N4

A novel mesoporous g-C3N4 loaded with biomass porous carbon was synthesized by molten salt assisted thermal polycondensation, and the formation of hollow tubular structure increased the specific surface area.

Optimization and Validation of a New Microbial Inhibition Test for the Detection of Antimicrobial Residues in Living Animals Intended for Human Consumption

Even though antibiotics are necessary in livestock production, they can be harmful not only due to their toxicity, but also in view of their contribution to the emergence of antimicrobial resistance. Screening tests based on microbial growth inhibition appeared to be useful tools to prevent its entry into the food chain. They have nevertheless been traditionally carried out post mortem, leading to great economical loss and harm to the environment in case a positive sample is found. Hence, the objective was to evaluate the use of a screening test as an ante mortem alternative for the detection of antibiotic residues in meat: thus, Explorer^®-Blood test was optimized and validated. After adapting the procedure for matrix preparation, the assay parameters were assessed from 344 antibiotic-free blood serum samples. Limits of Detection (LoDs) were defined by spiking blood serum with several of the most common antimicrobials used in veterinary practice. LoDs were similar to those obtained for meat and were at or below the maximum residue limits set by EU legislation for muscle. Analyses of in vivo injected samples, previously characterized by LC-MS/MS, demonstrated the method’s accuracy and proved that Explorer^®-Blood can be considered a suitable alternative to conventional post mortem screening methods.

Study on the Electrochemical Removal Mechanism of Oxytetracycline by a Ti/IrO2-Ta2O5 Plate

In this study, a Ti/IrO₂-Ta₂O₅ anode was prepared by a hydrothermal method, and the prepared electrode was characterized by techniques such as scanning electron microscopy, X-ray diffraction, and electron dispersive spectroscopy. At the same time, the anode characteristics before and after electrochemical experiments were analyzed. The electrode gradation mechanism of oxytetracycline is discussed. In the whole experimental process, the range of electrolysis conditions was determined by single factor experiment, and then the optimal removal condition of oxytetracycline was determined by orthogonal experiments. The removal rate of oxytetracycline reached 99.02% after 20 min of electrolysis under the following optimal conditions: a current of 0.500 A, plate spacing of 2 cm, Na₂SO₄ electrolyte concentration of 4 g/L, and solution pH of 3. Additionally, the mechanism of oxytetracycline removal was explored, free radical scavenging experiments were performed, and the degradation mechanism was inferred based on the changes in the ultraviolet absorption of the oxytetracycline solution before and after electrolysis. Then, based on the liquid chromatography-mass spectrometry data, seven possible compounds and five possible removal pathways were proposed.

Application of RNA-sequencing to identify biomarkers in broiler chickens prophylactic administered with antimicrobial agents

Antimicrobial (AM) resistance is largely acknowledged as one of the biggest global health and food safety challenges and the overuse of AMs is known to generate resistance in bacteria that may affect both animals and humans. Poultry meat is the second most-produced meat in the European Union and in recent years consumers are becoming more concerned about food safety, traceability, and animal welfare in poultry rearing system, increasingly requiring meats from broilers reared without AMs. In the present study, we performed RNA sequencing to analyze 64 liver and 54 muscle transcriptomic profiles in broilers reared without treatment or treated with different classes of AMs. Moreover, we validated the most differentially expressed genes among the treated groups to detect putative novel biomarkers able to discriminate meats of broilers reared without AMs. The PDK4, IGFBP1, and RHOB genes were identified as putative novel hepatic biomarkers, discriminating broilers treated with AMs compared to broilers reared without treatments. The whole transcriptome changes revealed the liver as a valuable target organ for AM administration screening. In addition, our results suggest a leading effect of the coccidiostat when associated with AMs, influencing several biological processes. Our study showed that RNA sequencing is a powerful and valuable method to detect aberrant regulated genes and to identify biomarker candidates for AM misuse detection in farm animals. Further validation on larger sample size and a wider spectrum of AMs are needed to confirm the viability of the aforementioned biomarkers in poultry population.

Determination of antibiotic residues in honey in relation to different potential sources and relevance for food inspection

Honey contaminations could derive from intensive agriculture and industrial activities, but also from beekeeper treatments. In EU no MRLs for antibiotics in honey are set, only a minimum required performance limit for chloramphenicol of 0.3 μg kg^-1 is recommended. Screening tests are available, characterised by their rapidity and simple use. Due to their high rate of false positives and the need to meet zero tolerance levels for antibiotics, their presence in samples was investigated using a liquid chromatography High Resolution Mass Spectrometry (LC-HRMS) multiclass antibiotic residue method, comparing the results with those of previous screening tests. The confirmatory method showed good sensitivity: CCα and CCβ ranging from 0.03 to 4.80 ng g^-1 and from 0.12 to 5.56 ng g^-1, respectively. Ninety-eight honey samples from different geographical areas, analysed by two screening tests, showed a high percentage of false positives. This is fundamental to guarantee honey safety, especially, for organic production.

Is Blood a Good Indicator for Detecting Antimicrobials in Meat? Evidence for the Development of In Vivo Surveillance Methods

The introduction of antimicrobial residues in the food chain has a significant impact on human health. An innovative solution to avoid their presence in meat is the adaptation of current control methods for use with in vivo matrixes. Thus, the aim was to obtain paired blood and muscle samples from pigs treated with some of the main antimicrobials currently used in veterinary medicine (oxytetracycline, sulfamethoxypyridazine, enrofloxacin, amoxicillin), and to compare their rate of depletion in both matrixes. Antimicrobial concentrations in paired samples of blood and muscle were determined by liquid chromatography with tandem mass spectrometry (LC-MS/MS) or high performance liquid chromatography with fluorescence detection (HPLC-FLD). A comparison between values obtained in muscle and blood showed a similar distribution in both matrixes for oxytetracycline; for sulfamethoxypyridazine, a similar decrease rate but a concentration three times higher in blood compared to muscle was found; for enrofloxacin, we found significant differences in the rate of depletion, with similar antimicrobial concentrations in both matrixes with values close to the maximum residue limit (MRL) and higher amounts in muscle for values that lay considerably over the MRL. Conversely, amoxicillin depletion was so rapid that its appearance in carcasses does not seem to pose a risk. Therefore, blood would be a feasible matrix for the development of new in vivo tests.

Feather analysis as a non-invasive alternative to tissue sampling for surveillance of doxycycline use on poultry farms

Intensive chicken production leads to overuse of antibiotics on poultry farms. For food safety control, there is great need for means to use non-conventional matrices allowing analysis of antibiotics during poultry breeding. The main goal of this study was to demonstrate feathers as suitable material for non-invasive detection of doxycycline treatment in poultry. Transfer to and depletion of doxycycline in chicken feathers were investigated after therapeutic, spray, and subtherapeutic treatment. For the quantitative determination of doxycycline in feathers, a validated ultra-high-performance liquid chromatography - tandem mass spectrometry method was used. High concentrations of doxycycline in feathers were detectable for 22 D post treatment in each experimental group, and they were much higher than those in muscle and liver. A washing experiment with the same solvent as for extraction showed different ratios between extractable and non-extractable residues in feathers of chickens treated therapeutically, by spraying and subtherapeutically, which demonstrates the ability of feather analysis to distinguish different forms of treatment. After a segmentation procedure, high amounts of doxycycline were found to be deposited in the upper part of feathers in each treatment group. The obtained results showed that chicken feathers are a suitable material for the detection and non-invasive surveillance of doxycycline.

Presence of emerging contaminants in baby food

Food safety becomes imperative when it aims to protect infants. The objective of this study was to investigate the presence of emerging contaminants of which some act as endocrine-disruptors in baby food. Persistent organic pollutants (POPs), perfluoroalkyl substances (PFASs), parabens and antibiotics were analysed in 112 baby food of different categories (meat, fish, vegetables, fruit, cheese). As regard POPs, PFASs and antibiotics, no residues were detected, while one sample showed methyl-paraben (4.14 ng g^-1), whereas another three contained propyl-paraben (median 1.70 ng g^-1). Special attention must be paid on parabens metabolites, as 4-hydroxybenzoic acid, the principal parabens metabolite, was detected in all samples (median 176.7 ng g^-1). It may be present as a degradation product, but also, it can be released from vegetables and fruits during food processing. It is recommended to collect more data on natural vs non-natural occurrence of parabens and metabolites to evaluate the exposure of sensitive population vs ADI published by the European Food Safety Authority and European Medicines Agency.

Assessing the depletion of lincomycin in feathers from treated broiler chickens: a comparison with the concentration of its residues in edible tissues

Lincomycin is the first antimicrobial agent described for the lincosamide class and it is commonly used for the treatment of infectious enteric and respiratory diseases in poultry. Maximum residue limits (MRLs) in edible tissues have been established for this antimicrobial, however, no regulation has been proposed yet for by-products that are not intended for direct human consumption. Feathers are a by-product from poultry farming that might be used as an ingredient for diets fed to other farm animal species. The presence of antimicrobial residues in them is not monitored in spite of the fact that several studies have proved that they can persist in feathers. Currently though, no evidence has been presented regarding the behaviour of lincomycin in this matrix. Hence, this work intended to assess the depletion of lincomycin residues in feathers of birds treated with therapeutic doses and compare them with those detected in muscle and liver samples. Samples were collected for several days after ceasing treatment from a group of broiler chickens treated with a 25% lincomycin formulation. Methanol and Florisil® columns were used to extract and retain the analyte, and samples were analysed using a triple quadrupole mass spectrometer (API 5500, AB SCIEX™). On day 1 after ceasing treatment, average concentrations of lincomycin detected in feather samples reached up to 8582 μg kg^-1 and by day 16, these had only declined by 63%, to an average of 3138 μg kg^-1. Lincomycin residues were detected in feathers at every sampling point, even after they were not detectable in edible tissues. Depletion time was 98 days for feathers, considering the LOQ established for the methodology as cut-off value for the calculations. Data showed that lincomycin is highly persistent in feathers, which may result in this matrix becoming a re-entry route for its residues into the food chain.

Electrochemical degradation of oxytetracycline by Ti-Sn-Sb/γ-Al2O3 three-dimensional electrodes

In this work, Ti-Sn-Sb/γ-Al₂O₃ particle electrodes were prepared and employed for the degradation of oxytetracycline (OTC) by three-dimensional electrocatalytic technology. Factors associated with the preparation of Ti-Sn-Sb/γ-Al₂O₃ particle electrodes were investigated. The effects of initial concentration, conductivity, pH value, aeration intensity, current density, plate spacing, and particle electrode dosage on OTC removal were studied. The removal rate of OTC and total organic carbon were achieved approximately 92.0% and 41.0% under the optimal operating condition, respectively. In addition, Ti-Sn-Sb/γ-Al₂O₃ particle electrode was analyzed by Fourier Transform Infrared spectroscopy (FT-IR), scanning electron microscope (SEM), energy dispersive spectrum analysis (EDX), X-Ray Fluorescence Spectrometer (XRF), and X Ray Diffraction analysis (XRD), which indicated that a significant amount of TiO₂, SnO₂, and Sb₂O₃ were formed on the surface of Ti-Sn-Sb/γ-Al₂O₃ particle electrode. It was also observed that the primary function of Ti-Sn-Sb/γ-Al₂O₃ particle electrode in the three-dimensional electrode electrolysis process is the strong oxidizing function of ·OH for degrading OTC. Consequently, the analysis of degradation products of oxytetracycline (OTC) demonstrates. In addition, the results and conclusions of this study provide a methodological basis and engineering practice basis for removing the low concentration of antibiotics in water.

Antimicrobial Resistance on Farms: A Review Including Biosecurity and the Potential Role of Disinfectants in Resistance Selection

Resistance to therapeutic antimicrobial agents is recognized as a growing problem for both human and veterinary medicine, and the need to address the issue in both of these linked domains is a current priority in public policy. Efforts to limit antimicrobial resistance (AMR) on farms have so far focused on control of the supply and use of antimicrobial drugs, plus husbandry measures to reduce infectious disease. In the United Kingdom and some other countries, substantial progress has been made recently against targets on agricultural antimicrobial drug use. However, evidence suggests that resistant pathogenic and commensal bacteria can persist and spread within and between premises despite declining or zero antimicrobial drug use. Reasons for this are likely complex and varied but may include: bacterial adaptations to ameliorate fitness costs associated with maintenance and replication of resistance genes and associated proteins, horizontal transmission of genetic resistance determinants between bacteria, physical transfer of bacteria via movement (of animals, workers, and equipment), ineffective cleaning and disinfection, and co-selection of resistance to certain drugs by use of other antimicrobials, heavy metals, or biocides. Areas of particular concern for public health include extended-spectrum cephalosporinases and fluoroquinolone resistance among Enterobacteriaceae, livestock-associated methicillin-resistant Staphylococcus aureus, and the emergence of transmissible colistin resistance. Aspects of biosecurity have repeatedly been identified as risk factors for the presence of AMR on farm premises, but there are large gaps in our understanding of the most important risk factors and the most effective interventions. The present review aims to summarize the present state of knowledge in this area, from a European perspective.