Estudo de depleção de fluorquinolonas e tetraciclinas em frangos de corte empregando LC-MS/MS

Abstract

Antibiotics have been widely used for prophylactic and therapeutic treatment within the broiler supply chain in order to improve animal production performance. The indiscriminate use of these drugs can, however, lead to the presence of residues in the meat and thus be a risk to the health of consumers. Fluoroquinolones and tetracyclines are two antibiotic classes that are commonly used in poultry. In this study, a liquid chromatography-based analytical method coupled with mass spectrometry was developed and validated in order to analyze residues of 7 antibiotics from the aforementioned classes in chicken muscle. Furthermore, antibiotic depletion studies were performed in broiler chickens in order to quantify the residues in the meat. The results were compared to maximum residue limits (MRLs) established by Brazilian and international laws. A procedure that employs acidified acetonitrile and purification by centrifugation and low temperature precipitation was used as the extraction method, with no need to perform a solid phase extraction (SPE) step. The method was validated in accordance with the Directive 2002/657/EC from the European Union by assessing selectivity, linearity and specificity parameters, detection and quantification limits, accuracy, precision, matrix effect, decision limit (CCα), detection capability (CCβ), robustness and applicability of the technique. For depletion studies, chlortetracycline (CTC), doxycycline (DOX) and oxytetracycline (OTC) were administered orally for 5 consecutive days and ciprofloxacin (CIP), enrofloxacin (ENR) and norfloxacin (NOR) for 3 days. After 6, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216 and 240 h after the last dose, muscle samples (chest) were collected from 4 animals from each treated group and from 2 from the control group in order to assess the residual concentration of the drugs. The validated method presented values within acceptable parameters according to Directive 2002/657/EC. From 65 chicken muscle samples evaluated for the applicability parameter, 3 presented residues of ENR. In the tetracyclines depletion studies, results showed that residues were under the MRLs considering Brazilian and European laws after 1 day for CTC and after 3 days for DOX. For OCT, this period was of 2 and 3 days according to Brazilian and European laws respectively. According to Japanese law, withdrawal time of 1, 5 and 2 days would be needed for CTC, DOX and OCT respectively. In the fluoroquinolones study, it was possible to detect traces of ENR even 9 days after treatment, which would make the export of meat to the United States and Canada infeasible. After 1 day at the last dose administrated, CIP residues were under MRLs established by Brazilian, European and Japanese laws, and after 4 days they were under limits determined by the Unites States and Canada. In the case of NOR, the withdrawal time would be of 1 day for all countries mentioned here. The results presented cooperate with the pursuit of food safety to consumers, as well as with the employment of analytical methods capable of determining drugs to comprise residue depletion studies in broilers.