title: Residue depletion of oxytetracycline (OTC) and 4-epi-oxytetracycline (4-epi-OTC) in broiler chicken's claws by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
abstract: Antibiotics are widely used in poultry production for the treatment of bacterial diseases. However, residues may remain in products and by-products destined for human consumption or animal feeding. The claws of chickens, which are a by-product of the poultry industry, can directly or indirectly enter the food chain as meals destined to feed other productive animals. Thus, it becomes necessary to determine and quantify antimicrobial residues present in this matrix. The objective of the study was to assess the depletion of oxytetracycline (OTC) and its metabolite 4-epi-OTC in broiler chicken's claws. Claws of 32 broilers treated with a therapeutic dosage of 10% OTC during 7 days were analysed. Samples were taken at days 3, 9, 15 and 19 post-treatment. As for the control group, eight broiler chickens were raised under the same conditions. Extraction was carried out through EDTA-McIlvaine buffer, and clean-up employed a SPE C-18 Sep-Pak®. Instrumental analysis was performed through LC-MS/MS. The concentrations of both analytes were determined in claw samples until day 19 post-treatment. Average concentrations were within the LOD (20 μg kg-1) and LOQ (22 µg kg-1) for OTC and 84 μg kg-1for 4-epi-OTC. Withdrawal times (WDTs) of 39 days for OTC and 54 days for 4-epi-OTC were established in claws based on 95% confidence. These findings demonstrate that claws can be a source of antimicrobial residue entry into the food chain, since the results showed that OTC and its metabolite can be found in chicken's claws for long periods, even exceeding the average lifespan of a broiler chicken.
authors.affiliation: a Preventive Medicine Department, Faculty of Veterinary and Animal Sciences , University of Chile , Santiago , Chile.
authors.forename: J
authors.initials: J
authors.lastname: Cornejo
authors.affiliation: a Preventive Medicine Department, Faculty of Veterinary and Animal Sciences , University of Chile , Santiago , Chile.
authors.forename: E
authors.initials: E
authors.lastname: Pokrant
authors.affiliation: a Preventive Medicine Department, Faculty of Veterinary and Animal Sciences , University of Chile , Santiago , Chile.
authors.forename: D
authors.initials: D
authors.lastname: Araya
authors.affiliation: a Preventive Medicine Department, Faculty of Veterinary and Animal Sciences , University of Chile , Santiago , Chile.
authors.forename: C
authors.initials: C
authors.lastname: Briceño
authors.affiliation: b Laboratory of Avian Pathology, Faculty of Veterinary and Animal Sciences , University of Chile , Santiago , Chile.
authors.forename: H
authors.initials: H
authors.lastname: Hidalgo
authors.affiliation: c Laboratory of Veterinary Pharmacology, Faculty of Veterinary and Animal Sciences , University of Chile , Santiago , Chile.
authors.forename: A
authors.initials: A
authors.lastname: Maddaleno
authors.affiliation: c Laboratory of Veterinary Pharmacology, Faculty of Veterinary and Animal Sciences , University of Chile , Santiago , Chile.
authors.forename: C
authors.initials: C
authors.lastname: Araya-Jordán
authors.affiliation: c Laboratory of Veterinary Pharmacology, Faculty of Veterinary and Animal Sciences , University of Chile , Santiago , Chile.
authors.forename: B
authors.initials: B
authors.lastname: San Martin
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000032:analysis* / Q000378:metabolism; D001711:Biotransformation; D002645:Chickens; D002677:Chile; D002853:Chromatography, Liquid; D004350:Drug Residues / Q000032:analysis* / Q000378:metabolism; D020387:Food Chain; D006724:Hoof and Claw / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D010118:Oxytetracycline / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000032:analysis* / Q000378:metabolism; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry
chemical_list: D000900:Anti-Bacterial Agents; D010118:Oxytetracycline
keywords: 4-epi-oxytetracycline (4-epi-OTC); LC-MS/MS; Oxytetracycline (OTC); antimicrobial; chicken’s claws; residues