Purpose: This study investigated the transfer of antibiotics from two antimicrobial families (tetracycline and chloramphenicol derivatives) to feathers and claws of therapeutically treated broiler chickens.
Methods: Broiler chickens (220, one-day-old) were kept with ad libitum access to water and nonmedicated feed. For each experiment, two experimental groups were formed: group (A) treated with a therapeutic dose, and group (B) not treated. Eighty birds were used for the oxytetracycline (OTC 10%) study in feathers and claws and 80 birds for florfenicol (FF 10%) in feathers and claws. After treatment, concentrations of the analytes were detected and quantified using LC-MS/MS.
Results: FF plus florfenicol-amine mean concentrations in feathers were 4,161 μg kg-1 at day five and 116 μg kg-1 at day 40 posttreatment. In claws, concentrations of 484 and 83 μg kg-1 were detected at day five post-treatment. OTC and 4-epi-oxytetracycline mean concentrations detected in feathers were 5,609 and 190 μg kg-1 at day five and 19 posttreatment, respectively. For claws, 299 and 104 μgkg-1were detected at the same sampling points.
Significance: High levels of antibiotics remained for longer periods in the studied byproducts of treated birds. Results demonstrate that these nonedible tissues may represent a risk for the reentry of antimicrobial residues into the food chain.