molecules-logo

Journal Browser

Journal Browser

Special Issue "Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Analytical Chemistry".

Deadline for manuscript submissions: closed (31 December 2018).

Special Issue Editors

Dr. Patricia Regal
E-Mail Website
Guest Editor
Laboratorio de Higiene Inspección y Control de Alimentos, Facultad de Veterinaria pabellón 4 p.b, Campus Universitario, 27002 Lugo, Spain
Interests: food safety; analytical chemistry; growth promoters; steroids; hormones; fatty acids; veterinary drugs; mycotoxins; chromatography; mass spectrometry; profiling; omics; metabolomics; bioinformatics; molecularly imprinted polymers; food-borne pathogens
Special Issues and Collections in MDPI journals
Prof. Dr. Carlos M. Franco
E-Mail Website
Guest Editor
Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Science, University of Santiago de Compostela, 27002-Lugo, Spain
Interests: food safety; analytical chemistry; food microbiology; antimicrobial resistant bacteria; food-borne pathogens; transcriptomics; genotyping; chromatography; mass spectrometry; biofilms; antimicrobial detection; Microbiome
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

In the face of actual increasing demand for food worldwide, small farms are slowly disappearing, only to be replaced by large commercial farms and intensive productive systems. In this context, the rational use of veterinary drugs in stockfarming has greatly contributed to achieving current high production rates of food of animal origin, along with considerable profits. Veterinary drugs are pharmacologically active substances that may be administered to animals in order to maintain and/or to restore an optimal health status, or for zootechnical purposes. Their major applications in farm animals include: treatment of infection, pain relief, control of inflammation, immunity modulation, tranquilization and/or sedation, parasitic control, fertility management, or growth promotion, amongst others. Strictly, veterinary drugs can also be administered to sports, companion, or wild animals, but this application is not as important as in animal husbandry in terms of food safety—at least not directly.

The use of veterinary drugs in food-producing animals has the potential to generate residues in their edible products (meat, milk, eggs, and honey), and in this sense the administration of these compounds must be controlled and monitored, as residues may pose a health hazard for the consumer. Accordingly, maximum residue limits in different animal-derived products are frequently established by regulatory agencies for permitted drugs. In the case of banned compounds, such as growth promoters in EU, a zero-tolerance policy is applied. In order to measure the low residue levels that are usually found in food and animal matrices, highly selective, sensitive, and accurate methodology is required. Analytical methods for veterinary residue analysis have evolved greatly in the last decades, in parallel to the large number of drugs existing on the veterinary market. On the basis of this , multi-residue/multi-class methods have grown exponentially, including also profiling approaches and the determination of unknowns (omics) for the indirect detection of drug administration.

This Special Issue welcomes original research and reviews of literature on modern solutions for monitoring veterinary drugs in food, including the determination of permitted and banned drugs, but also other borderline compounds such as natural hormones and pro-hormones. Contributions must reflect the state-of-the-art on the topic, and analytical methods must be properly validated according to official guidelines. The final goal of this compilation of scientific papers is to serve as inspiration and source of knowledge for future analysts and residue laboratories worldwide. Potential topics include, but are not limited to:

  • Multi-analyte, multi-residue, and/or multi-class analytical methods in food and/or animal matrices (food safety and control in vivo)
  • Novel “omics” technologies (metabolomics, proteomics, transcriptomics, lipidomics...)
  • Profiling and similar indirect approaches
  • Trends in screening solutions
  • Reviews of literature on modern solutions

Dr. Patricia Regal
Dr. Carlos M. Franco
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • veterinary drug
  • growth promoter
  • steroids
  • analytical method
  • chromatography
  • mass spectrometry
  • food safety
  • omics
  • profiling
  • multi-residue
  • multi-class
  • multi-analyte

Published Papers (11 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Open AccessArticle
Tetracycline Residues in Bovine Muscle and Liver Samples from Sicily (Southern Italy) by LC-MS/MS Method: A Six-Year Study
Molecules 2019, 24(4), 695; https://doi.org/10.3390/molecules24040695 - 15 Feb 2019
Cited by 7 | Viewed by 1065
Abstract
We examined a total of 369 bovine liver and muscle samples for the detection of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOX) residues by implementation and validation of a LC-MS/MS method. The method showed good recovery values between 86% and 92% [...] Read more.
We examined a total of 369 bovine liver and muscle samples for the detection of oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC), and doxycycline (DOX) residues by implementation and validation of a LC-MS/MS method. The method showed good recovery values between 86% and 92% at three levels of concentrations. The linearity tests revealed r2 > 0.996 for all the tetracyclines examined. Furthermore, the Youden test revealed that the method was robust. Only 14.4% of the samples showed OTC and TC residues in a concentration range of 10.4–40.2 µg kg−1. No CTC and DOX residues were found in all the samples analyzed. Liver samples showed the highest average values (31.5 ± 20.6 and 21.8 ± 18.9 for OTC and TC, respectively). The results showed a low incidence of TCs in all the samples examined, in comparison with other studies reported in the literature. A significant decrease in TC residues frequency was found from 2013 (p < 0.05). This work reports for the first time epidemiological data on the presence of TC residues in liver and muscle samples of cattle farmed in Sicily (Southern Italy). The very low incidence of TC residues indicates a continuous improvement in farming techniques in Southern Italy, which is essential to ensure consumers’ protection. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Graphical abstract

Open AccessArticle
Deltamethrin Residues in Milk and Cheese of Lactating Goats (Capra hircus)
Molecules 2019, 24(3), 517; https://doi.org/10.3390/molecules24030517 - 31 Jan 2019
Cited by 1 | Viewed by 1357
Abstract
The distribution of pyrethroid insecticide deltamethrin (DLM) in goat milk and cheese (caciotta) following pour-on administration at the sheep dosage (DLMS-10 mL/60 kg body weight) and double dosage (DLMD-20 mL/60 kg body weight) was studied. DLM concentrations were measured in milk collected from [...] Read more.
The distribution of pyrethroid insecticide deltamethrin (DLM) in goat milk and cheese (caciotta) following pour-on administration at the sheep dosage (DLMS-10 mL/60 kg body weight) and double dosage (DLMD-20 mL/60 kg body weight) was studied. DLM concentrations were measured in milk collected from study animals (No.14) before treatment and at 2, 4, 8, 12, 16, 24, 30, 36, 48, 56, until 168 h (7 days) post treatment and in caciotta cheese at 12 and 24 h post treatment. At both dosages, the maximum level of DLM residues in goat milk and cheese was below the maximum residue limit (MRL) of 20 μg kg−1 established for bovine milk (EU No 37/2010) at all time points. However, in terms of public health, higher DLM residues in cheese show that further specific studies should be performed on double dosage efficacy and pharmacokinetic and pharmacodynamics properties of ectoparasites in lactating goats. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Graphical abstract

Open AccessArticle
Determination of Sulfonamides in Feeds by High-Performance Liquid Chromatography after Fluorescamine Precolumn Derivatization
Molecules 2019, 24(3), 452; https://doi.org/10.3390/molecules24030452 - 28 Jan 2019
Cited by 4 | Viewed by 1252
Abstract
A new multi-residue method for the analysis of sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfaguanidine and sulfamethoxazole) in non-target feeds using high-performance liquid chromatography-fluorescence detection (HPLC-FLD) and precolumnderivatization was developed and validated. Sulfonamides (SAs) were extracted from feed with an ethyl acetate/methanol/acetonitrile mixture. Clean-up was [...] Read more.
A new multi-residue method for the analysis of sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfaguanidine and sulfamethoxazole) in non-target feeds using high-performance liquid chromatography-fluorescence detection (HPLC-FLD) and precolumnderivatization was developed and validated. Sulfonamides (SAs) were extracted from feed with an ethyl acetate/methanol/acetonitrile mixture. Clean-up was performed on a Strata-SCX cartridge. The HPLC separation was performed on a Zorbax Eclipse XDB C18 column with a gradient mobile phase system of acetic acid, methanol, and acetonitrile. The method was validated according to EU requirements (Commission Decision 2002/657/EC). Linearity, decision limit, detection capability, detection and quantification limits, recovery, precision, and selectivity were determined, and adequate results were obtained. Using the HPLC-FLD method, recoveries were satisfactory (79.3–114.0%), with repeatability and reproducibility in the range of 2.7–9.1% to 5.9–14.9%, respectively. Decision limit (CCα) and detection capability (CCβ) were 197.7–274.6 and 263.2–337.9 µg/kg, respectively, and limit of detection (LOD) and limit of quantification (LOQ) were 34.5–79.5 and 41.3–89.9 µg/kg, respectively, depending on the analyte. Results showed that this analytical procedure is simple, rapid, sensitive, and suitable for the routine control of feeds. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Graphical abstract

Open AccessArticle
A Class-Selective Immunoassay for Sulfonamides Residue Detection in Milk Using a Superior Polyclonal Antibody with Broad Specificity and Highly Uniform Affinity
Molecules 2019, 24(3), 443; https://doi.org/10.3390/molecules24030443 - 26 Jan 2019
Cited by 6 | Viewed by 1427
Abstract
The development of multianalyte immunoassays with an emphasis on food safety has attracted increasing interest, due to its high target throughput, short detection time, reduced sample consumption, and low overall cost. In this study, a superior polyclonal antibody (pAb) against sulfonamides (SAs) was [...] Read more.
The development of multianalyte immunoassays with an emphasis on food safety has attracted increasing interest, due to its high target throughput, short detection time, reduced sample consumption, and low overall cost. In this study, a superior polyclonal antibody (pAb) against sulfonamides (SAs) was raised by using a bioconjugate of bovine serum albumin with a rationally designed hapten 4-[(4-aminophenyl) sulfonyl-amino]-2-methoxybenzoic acid (SA10-X). The results showed that the pAb could recognize 19 SAs with 50% inhibition (IC50) below 100 µg L−1 and a recognition profile for SAs containing, either a five-atom ring or a six-atom ring, with highly uniform affinity. A three-dimensional quantitative structure-activity relationship analysis indicated that the electrostatic features of SAs play a considerably important role, during recognition with pAb than stereochemical effects. Skimmed milk samples were directly diluted five times before analysis. After optimization, the limit of detection for sulfamonomethoxine, sulfamethoxazole, sulfaquinoxaline, sulfadimethoxine, and sulfamethazine were 1.00, 1.25, 2.95, 3.35, and 6.10 µg L−1, respectively. The average recoveries for these 5 SAs were 72.0–107.5% with coefficients of variation less than 14.1%. The established method, based on pAb, with broad specificity and uniform affinity, offered a simple, sensitive, and high-throughput screening tool for the detection of multi-SAs in milk samples. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Graphical abstract

Open AccessFeature PaperArticle
New Poly(Ionic Liquid) Based Fiber for Determination of Oxytetracycline in Milk Samples by Application of SPME-CE Technique
Molecules 2019, 24(3), 430; https://doi.org/10.3390/molecules24030430 - 24 Jan 2019
Cited by 4 | Viewed by 1164
Abstract
In this work, a procedure using solid phase microextraction in combination with capillary electrophoresis was developed for the determination of oxytetracycline in milk samples. The method involves the synthesis of poly(1-allyl-3-methyl imidazolium) chloride film on a stainless-steel bar via electropolymerization and its use [...] Read more.
In this work, a procedure using solid phase microextraction in combination with capillary electrophoresis was developed for the determination of oxytetracycline in milk samples. The method involves the synthesis of poly(1-allyl-3-methyl imidazolium) chloride film on a stainless-steel bar via electropolymerization and its use as an adsorbent for oxytetracycline (OT) by an ionic exchange mechanism. The coated fiber is then immersed in milk samples for retention of oxytetracycline residues, followed by elution, drying, and reconstitution before analysis with capillary electrophoresis. The proposed method achieves a limit of detection of 70 µg L−1 with adequate precision and uncertainty, making this methodology appropriate for the determination of OT in milk samples. The method was applied to the pre-concentration and quantification of oxytetracycline in ten commercial milk samples. Two tested samples were positive for the presence of oxytetracycline but the concentration was below the maximum residue limit according to the international normative standard. The proposed methodology was evaluated according to the Eco-Scale approach, and the total score of 51 indicated that the methodology proposed is both green and acceptable despite the multi-stage character. SPME-CE methodology allows us to perform the sample pre-treatment and determination of OT in an effective and greener way, decreasing the number of steps during the analysis and the generation of waste. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Figure 1

Open AccessArticle
QuEChERS and HPLC-MS/MS Combination for the Determination of Chloramphenicol in Twenty Two Different Matrices
Molecules 2019, 24(3), 384; https://doi.org/10.3390/molecules24030384 - 22 Jan 2019
Cited by 6 | Viewed by 1057
Abstract
A simple method for the determination of chloramphenicol in 22 matrices was prepared based on the QuEChERS and HPLC-MS/MS combination. Following a hydrolysis step, the homogenized samples were extracted and partitioned after adding sodium chloride with acetonitrile. Chloramphenicol was analysed by HPLC-MS/MS in [...] Read more.
A simple method for the determination of chloramphenicol in 22 matrices was prepared based on the QuEChERS and HPLC-MS/MS combination. Following a hydrolysis step, the homogenized samples were extracted and partitioned after adding sodium chloride with acetonitrile. Chloramphenicol was analysed by HPLC-MS/MS in negative electrospray mode by monitoring the daughter ions m/z: 321→194 and 321→152. The limit of decision (CCα) was calculated at the range of 0.10 μg kg−1 to 0.15 μg kg−1 and detection capability (CCβ) from 0.12 μg kg−1 to 0.18 μg kg−1. Validation results showed that this method is suitable for the determination and confirmation of chloramphenicol in various matrices. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Figure 1

Open AccessArticle
Residue Depletion of Florfenicol and Florfenicol Amine in Broiler Chicken Claws and a Comparison of Their Concentrations in Edible Tissues Using LC–MS/MS
Molecules 2018, 23(9), 2211; https://doi.org/10.3390/molecules23092211 - 31 Aug 2018
Cited by 1 | Viewed by 1496
Abstract
Antimicrobial residues might persist in products and by-products destined for human or animal consumption. Studies exploring the depletion behavior of florfenicol residues in broiler chicken claws are scarce, even though claws can enter the food chain directly or indirectly. Hence, this study intended [...] Read more.
Antimicrobial residues might persist in products and by-products destined for human or animal consumption. Studies exploring the depletion behavior of florfenicol residues in broiler chicken claws are scarce, even though claws can enter the food chain directly or indirectly. Hence, this study intended to assess the concentrations of florfenicol (FF) and florfenicol amine (FFA)—its active metabolite—in chicken claws from birds that were treated with a therapeutic dose of florfenicol. Furthermore, concentrations of these analytes in this matrix were compared with their concentrations in edible tissues at each sampling point. A group of 70 broiler chickens were raised under controlled conditions and used to assess residue depletion. Sampling points were on days 5, 10, 20, 25, 30, 35, and 40 after ceasing treatment, thus extending beyond the withdrawal period established for muscle tissue (30 days). Analytes were extracted using HPLC-grade water and acetone, and dichloromethane was used for the clean-up stage. Liquid chromatography coupled to mass spectroscopy detection (LC–MS/MS) was used to detect and quantify the analytes. The analytical methodology developed in this study was validated in-house and based on the recommendations described in the Commission Decision 2002/657/EC from the European Union. Analyte concentrations were calculated by linear regression analysis of calibration curves that were fortified using an internal standard of chloramphenicol-d5 (CAF-d5). The depletion time of FF and FFA was set at 74 days in claws, based on a 95% confidence level and using the limit of detection (LOD) as the cut-off point. Our findings show that FF and FFA can be found in chicken claws at higher concentrations than in muscle and liver samples at each sampling point. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Graphical abstract

Open AccessArticle
Assessment of Binding Interaction between Bovine Lactoferrin and Tetracycline Hydrochloride: Multi-Spectroscopic Analyses and Molecular Modeling
Molecules 2018, 23(8), 1900; https://doi.org/10.3390/molecules23081900 - 30 Jul 2018
Cited by 7 | Viewed by 1842
Abstract
In this paper, the interaction between bovine lactoferrin (bLf) and tetracycline hydrochloride (TCH) was researched by microscale thermophoresis (MST), multi-spectroscopic methods, and molecular docking techniques. Normal fluorescence results showed that TCH effectively quenched the intrinsic fluorescence of bLf via static quenching. Moreover, MST [...] Read more.
In this paper, the interaction between bovine lactoferrin (bLf) and tetracycline hydrochloride (TCH) was researched by microscale thermophoresis (MST), multi-spectroscopic methods, and molecular docking techniques. Normal fluorescence results showed that TCH effectively quenched the intrinsic fluorescence of bLf via static quenching. Moreover, MST confirmed that the combination force between bLf and TCH was very strong. Thermodynamic parameters and molecular docking further revealed that electrostatic forces, van der Waals, and hydrogen bonding forces played vital roles in the interaction between bLf and TCH. The binding distance and energy transfer efficiency between TCH and bLf were 2.81 nm and 0.053, respectively. Moreover, the results of circular dichroism spectra (CD), ultraviolet visible (UV-vis) absorption spectra, fluorescence Excitation-Emission Matrix (EEM) spectra, and molecular docking verified bLf indeed combined with TCH, and caused the changes of conformation of bLf. The influence of TCH on the functional changes of the protein was studied through the analysis of the change of the bLf surface hydrophobicity and research of the binding forces between bLf and iron ion. These results indicated that change in the structure and function of bLf were due to the interaction between bLf and TCH. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Figure 1

Open AccessArticle
Quick Multi-Class Determination of Residues of Antimicrobial Veterinary Drugs in Animal Muscle by LC-MS/MS
Molecules 2018, 23(7), 1736; https://doi.org/10.3390/molecules23071736 - 16 Jul 2018
Cited by 5 | Viewed by 1635
Abstract
On the basis of the highly sensitive and selective liquid chromatography-tandem mass spectrometry technique, a generic extraction solvent and a sample dilution method was developed for the residue analysis of different polar veterinary drugs known as fluoroquinolones, sulfonamides, macrolides, and tiamulin in chicken [...] Read more.
On the basis of the highly sensitive and selective liquid chromatography-tandem mass spectrometry technique, a generic extraction solvent and a sample dilution method was developed for the residue analysis of different polar veterinary drugs known as fluoroquinolones, sulfonamides, macrolides, and tiamulin in chicken muscle. The results showed that the matrix-matched calibration curves of all 10 compounds were in an effective linear relationship (r2 ≥ 0.997) in the range of 0.2–100 μg L−1. At three spiking levels of 2 (5), 50, and 100 μg kg−1, average recoveries of analytes were between 67.1% and 96.6% with relative standard deviations of intra-day and inter-day below 20%. The limits of detection and limits of quantification of the method were in the range of 0.3–2.0 μg kg−1 and 2.0–5.0 μg kg−1, respectively, which were significantly lower than their maximum residue limits. In addition, the intensity of the target analytes and its corresponding matrix effects were obviously related to the sample dilution times (matrix concentration). There were no significant differences (p > 0.05) in the average content of almost any of the analytes in medicated chickens between this method and the method in the literature for determining analytes. Lastly, the proposed method was successfully applied for the simultaneous analysis of 10 common veterinary drugs in food animal muscle tissues. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Graphical abstract

Open AccessFeature PaperArticle
Tracing Recombinant Bovine Somatotropin Ab(Use) Through Gene Expression in Blood, Hair Follicles, and Milk Somatic Cells: A Matrix Comparison
Molecules 2018, 23(7), 1708; https://doi.org/10.3390/molecules23071708 - 13 Jul 2018
Cited by 3 | Viewed by 1624
Abstract
The use of recombinant bovine somatotropin (rbST) in dairy cattle is forbidden in the European Union. Due to the very low circulating concentration of rbST in treated animals, its direct detection is still a challenge. Therefore, the use of indirect methods to detect [...] Read more.
The use of recombinant bovine somatotropin (rbST) in dairy cattle is forbidden in the European Union. Due to the very low circulating concentration of rbST in treated animals, its direct detection is still a challenge. Therefore, the use of indirect methods to detect the ab(use) of rbST in dairy cattle appears as a good alternative. In the past few years, gene expression demonstrated its utility in screening the use of illicit substances in both humans and animals. In this study, a comparison of three types of matrices (milk somatic cells, blood, and hair follicles) was carried out to evaluate their potential use for routine control of rbST using 15 gene-expression profiles. A total of six rbST-treated cows and three control cows were included in the study. A subcutaneous injection containing 500 mg of rbST was administered to the treated group. Samples of the three matrices were collected before rbST administration, and at three and nine days after treatment. The quality of RNA extracted was higher in the blood and hair-follicle samples than in the milk somatic cells. In the three matrices, there were significant differences in the expression of some genes, with milk somatic cells and blood presenting the the best matrices. On this note, the cyclin D1 (CCND1), interleukin 1 beta (IL-1β), tumor necrosis factor (TNF), and insulin-like growth factor 1 receptor (IGF-1R) genes showed potential as biomarkers of rbST treatment. Therefore, blood, somatic cells, and follicle hair should be considered as promising sources of RNA, and can be used in gene-expression assays to routinely control the illicit use of rbST. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Figure 1

Open AccessArticle
Determination of Chlortetracycline Residues, Antimicrobial Activity and Presence of Resistance Genes in Droppings of Experimentally Treated Broiler Chickens
Molecules 2018, 23(6), 1264; https://doi.org/10.3390/molecules23061264 - 25 May 2018
Cited by 6 | Viewed by 1751
Abstract
Tetracyclines are important antimicrobial drugs for poultry farming that are actively excreted via feces and urine. Droppings are one of the main components in broiler bedding, which is commonly used as an organic fertilizer. Therefore, bedding becomes an unintended carrier of antimicrobial residues [...] Read more.
Tetracyclines are important antimicrobial drugs for poultry farming that are actively excreted via feces and urine. Droppings are one of the main components in broiler bedding, which is commonly used as an organic fertilizer. Therefore, bedding becomes an unintended carrier of antimicrobial residues into the environment and may pose a highly significant threat to public health. For this depletion study, 60 broiler chickens were treated with 20% chlortetracycline (CTC) under therapeutic conditions. Concentrations of CTC and 4-epi-CTC were then determined in their droppings. Additionally, this work also aimed to detect the antimicrobial activity of these droppings and the phenotypic susceptibility to tetracycline in E. coli isolates, as well as the presence of tet(A), tet(B), and tet(G) resistance genes. CTC and 4-epi-CTC concentrations that were found ranged from 179.5 to 665.8 µg/kg. Based on these data, the depletion time for chicken droppings was calculated and set at 69 days. All samples presented antimicrobial activity, and a resistance to tetracyclines was found in bacterial strains that were isolated from these samples. Resistance genes tet(A) and tet(B) were also found in these samples. Full article
(This article belongs to the Special Issue Trends in Veterinary Drug Analysis: Multiresidue and Omic Approaches)
Show Figures

Graphical abstract

Back to TopTop