Tissue depletion of five antibiotic residues in farmed European seabass (Dicentrarchus labrax)

Concerns about antibiotic use led to stricter legislations and overall better practices in aquaculture production. However, depletion time periods in tissues vary greatly with different antimicrobials, fish species, or experimental setup. In the present work, five drugs (sulfadiazine (SDZ), trimethoprim (TRI), flumequine (FLU), oxolinic acid (OXO), and oxytetracycline (OTC)) were incorporated into medicated feed, and their retention in European seabass muscle tissues assessed. Juveniles were placed in 300 L tanks at 18 °C and were manually fed with medicated feeds for a 7 day period (two concentrations per antimicrobial, ranging from 6 to 220 mg kg−1 , which were based on previous studies on the occurrence of these antimicrobials). Residues were analyzed through a multi-class quantification method (UHPLC-MS/MS). Data on residues concentration through time followed a one-compartment model, with TRI concentrations above the established Maximum Residue Level (MRL) throughout the experiment. Similarly, OTC concentrations at the highest dose were also above 100 μg kg−1 up to 14 days after the medication period. Results obtained for TRI may indicate the presence of a dose dependency for this antimicrobial. FLU concentrations in muscle samples were the lowest through time (Cday7 of 279.70 and 386.63 μg kg−1 , for prophylactic and therapeutic treatments, respectively). Half-life values of 14.37, 10.87, 5.36, 7.20, and 27.22 h (prophylactic treatment), and 20.95, 8.41, 5.61, 11.22, and 17.99 h (therapeutic treatment), were determined for SDZ, TRI, FLU, OXO, and OTC, respectively. Withdrawal times of 0, 2, and 5 days were determined for FLU, OXO, and SDZ, but sampling times for OTC and TRI should be longer, since antimicrobial concentrations were above the MRL 14 days after the end of the feeding period with medicated feed. Therefore, special attention should be given since they are the most used antibiotics in aquaculture and European seabass plays a major part in human nutrition in the Mediterranean region.

Description

Financial support was given by FEDER through the Operational Program for Competitiveness Factors and COMPETE, through FCT and the Portuguese Foundation for Science and Technology under project PTDC/AGR/ALI/122119/2010, and projects ReNATURE - Valorization of the Natural Endogenous Resources of the Centro Region (Centro 2020, Centro-01-0145-FEDER-000007) and SmarBioR - Smart Valorization of Endogenous Marine Biological Resources Under a Changing Climate (Centro 2020, Centro-01-0145-FEDER-000018), cofunded by Centro 2020 Program, Portugal 2020, European Union, through the European Regional Development Fund. Authors also acknowledge FCT for the grant attributed to Sara Leston (grant SFRH/ BPD/91828/2012) and to João Rosa (grant SFRH/BD/102008/2014). The funding source did not interfere with the study design, or in the collection, analysis or interpretation of the data. It also had no involvement in the writing of the report and in the decision to submit the present manuscript for publication.

Keywords

Seabass Medicated feed Withdrawal times Retention Residues

URI

http://hdl.handle.net/10400.8/4188

Citation

Rosa, J., Leston, S., Freitas, A., Barbosa, J., Ramos, F., Pardal, M. A., … Lemos, M. F. L. (2019). Tissue depletion of five antibiotic residues in farmed European seabass (Dicentrarchus labrax). Aquaculture, 498, 413–421. https://doi.org/10.1016/j.aquaculture.2018.08.035