Avaliação da presença de resíduos de antimicrobianos, por HPLC/MS-MS, em rim de frangos de corte submetidos a tratamento farmacológico | Evaluation of the presence of antimicrobial residues, by HPLC/MS-MS, in the kidneys of broiler chickens subjected to pharmacological treatment

The objective of this study was to evaluate the presence and residue levels of five antimicrobials in the kidneys of broilers using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC/MS-MS). A total of 240 Cobb broilers were housed in twelve experimental pens containing 20 birds each. The treatments, defined according to the antimicrobial administered to the birds via drinking water, were as follows: A) birds that received no medication (control); B) birds that received tylosin via feed; C) birds that received lincomycin via feed; D) birds that received enrofloxacin in the drinking water; E) birds that received sulfaquinoxaline in the drinking water; and F) birds that received oxytetracycline in the drinking water. Treatments B and C were administered to the animals from day 1 to day 35 of rearing, while treatments D, E, and F were administered on days 32, 33, and 34 of rearing. The birds in groups A, B, and C were slaughtered on days 35, 36, 38, and 40, while the birds in groups D, E, and F were slaughtered on days 33, 34, 35, 36, 38, and 40 for kidney collection to evaluate the presence of residues of the antimicrobials used. The results of the analysis of the kidney samples from the broilers for the analytes tylosin and lincomycin demonstrated that the presence of residues of these antimicrobials was not detected, since all the signals were below the detection limit (LD) of the method used, for all the days of slaughter of the animals. The results of the analysis of kidney samples from broilers for the analytes enrofloxacin and sulfaquinoxaline demonstrated the presence of residues of these antimicrobials, at concentrations above the maximum residue limits (MRLs) for each drug, up to day 36 (two days after the end of treatment) and day 37 (three days after the end of treatment) of rearing, respectively. The analyte oxytetracycline showed results above the MRL only on day 34 of rearing (the last day of treatment). It was also observed that five days after drug withdrawal, for all drugs evaluated, the residue concentrations found were below the limit of quantification (LQ) of the method. It was concluded that all antimicrobials used are rapidly metabolized by the organisms of broilers, since five days after the end of treatments, no more residues of the evaluated drugs were detected.

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