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Monitoring the presence of Antibiotics and Coccidiostats Residues in Feed: a case-control study on Spanish dairy farms

Badania monitoringowe pozostałości antybiotyków i kokcydiostatyków w paszach: wyniki badań kontrolnych z ferm mlecznych w Hiszpanii

s. 17

Carolina Nebot*, Rosa Elvira Gavilán, Maria Veiga-Gómez, Jose Manuel Miranda, Carlos Manuel Franco, Alberto Cepeda

Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Veterinary Medicine, University of Santiago de Compostela, 27002, Lugo, Spain.

Key words: antimicrobials, coccidiostats, HPLC-MS/MS, validation, feed

Słowa klucze: substancje przeciwbakteryjne, kokcydiostatyki, HPLC-MS/MS, walidacja, pasze

According to data reported by FEFAC (European Feed Manufacturers' Federation) the global feed production is estimated to be around 989 Mt being approximately 16% (153.4 mio.t.) produced in the European Union and in particular in Germany (24%), Spain (22%) and France (20%).

During 2016 Spain produced approximately 34 Mt of feed for porcine, bovine, poultry, fish and pets.  Medicated feed represented the 11% of the total feed being 9.6% medicated feed with antimicrobial agents.  Spain sold 2964 t of antimicrobial during 2015 and the groups  more frequently sold were Tetracyclines (33%), Penicillins (23%), Sulfonamides (11%) and  Polymyxins (9%).  It should be highlighted that 70% of the antimicrobial were sold as a form of premixes.

Even if coccidiostats, sulfonamides, tetracyclines and trimethoprim are active substances permitted in animal feed for the prevention or the treatment of animal diseases, residues of tetracycline and sulfonamides in non-target feed are forbidden within the European Union. On the other hand, since 2009 residues of coccidiostats are acceptable but only up to a maximum level included in the European Regulation 574/2011.

The aim of this work is to present an HPLC-MS/MS confirmatory method for the simultaneous determination of traces levels (μg/kg) of coccidiostats, sulfonamides and trimethoprim in non-target feed. The method has been validated according to Commission Decision 2002/657/EC and applied to feed samples collected in 118 milk farms form the province of Lugo.  The antimicrobial more frequently detected were sulfadiazine and sulfadimidine measured in 20 and 9 samples respectively. Regarding coccidiostats decoquinate was the most frequently detected but always at concentration below the maximum level set up by the European Legislation. These results indicated that the present of antimicrobial in non-target feed occurred and more monitoring control at residual level should be conducted to avoid the incidence of bacterial with resistant genes in the future.


  1. Anon: Commission Decision 2002/657/EC. 2002. of 12 August implementing Council Directive 96/23/EC concerning the performance of analytical methods and the interpretation of results. OJ. L 221:8–36.
  2. ESVAC, 2015. European Medicines Agency, European Surveillance of Veterinary Antimicrobial Consumption, 2017. ‘Sales of veterinary  antimicrobial agents in 30 European countries in 2015’. (EMA/184855/2017). Accessed on the 10th of October, 2017 via
  3. European Commission. 2011. Regulation (EC) No 574/2011 of 16 June 2011 amending Annex I to Directive 2002/32/EC of the European Parliament and of the Council as regards maximum levels for nitrite,  melamine, Ambrosia spp. and carry-over of coccidiostats or histomonostats in non-target feed. Off J Eur Commun. L40:19–25.