Distribution of Antibiotic Residues in Non-medicated Poultry Feeds by High-Performance Liquid Chromatography with Diode-array Detection

Abstract

This paper reports on the determination and distribution of antibiotic drugs in poultry feeds mainly the layers and growers mash obtained from Ogun state in Nigeria. Pulverized feed samples were initially treated with phosphate buffer adjusted to pH 7 and the analytes extracted in an SPE cartridge with ammonium hydroxide and methanol. The extract reconstituted in phosphate buffer was determined with high-performance liquid chromatography-diode array detection (HPLC-DAD). The analytical column was an XTerra MS C18 column, (4.6 mm x 100 mm, 3.5 μm) with mobile phases consisting of ultrapure water and acetonitrile mixed with 0.1% HCOOH in gradient elution mode. Data acquisition was achieved with AgilentChemStation Version B.040.01 SP1 while the analytes were completely separated under 10 minutes with good resolution and symmetric peaks. The high correlation coefficient (R2) values (> 0.998, excluding sulfadimethoxine) indicate a good correlation between analyte concentration and peak areas. Limit of detection (LOD) and quantitation (LOQ) was between 5.37 and 55.42 ng/g, and 17.91 and 184.74 ng/g, respectively. All the drugs exhibited high mean concentration values in the two feed types, and there was no significant difference between their means (p < 0.05). The results clearly showed that feed millers fortify their feeds with antibiotics mainly sulfonamides in varying amounts without declaring same, thus compromising security of poultry birds and human consumers.