Target Analysis of Antibiotic Drugs in Poultry Feedstuff by Solid Phase Extraction and Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

Seventy-five poultry feed samples of two feed types were analysed for antibiotic drugs using a simple generic solid phase extraction procedure with dichloromethane-acetonitrile after delipidation with n-hexane. Analytical separation was performed on a Waters Acquity C18 column with gradient elution consisting of water and acetonitrile. Liquid chromatography-tandem mass spectrometry (LC-MS/MS), with positive and negative electrospray ionization methods in the multiple reaction monitoring modes (MRM), was used for the quantification of 21 compounds from six classes including fluoroquinolones, sulfonamides, lincosamides, anthelmintics, macrolides and the beta-lactams in a single chromatographic run of 14 minutes. All the six classes of the drugs were found in the two feed types at concentration ranging between 0.22 - 1505 ng/g. Sulfadimethoxine, sulfaguanidine, sulfamerazine, and sulfamethoxazole were the major sulfonamides in the two feed types with concentration at the part per million levels. Albendazole, penicillin-G, sulfadiazine, sulfaquinoxaline and sulfixosazole were not detected in the layers mash exclusively fed to laying birds; also, sulfamethazine and sulfamozole were the only two drugs not detected in the growers mash meant for birds raised for meat. Ciprofloxacin, sulfadimethoxine, sulfamethoxazole, sulfamerazine, and sulfaguanidine were the most prominent antibiotic drugs in the two feed types. Results from the present study suggest that feed millers surreptitiously fortify their feeds with antibiotics without declaring same, thus exposing poultry chickens to sub-therapeutic dosages of the drugs. It is evident that self-regulation for safety in the poultry industry should be discouraged thus relevant authorities must take steps to reduce and control the use of antibiotics to protect public health.