DETECTING SULFAMETHAZINE RESIDUES IN CHICKEN TISSUES USING THE DELVOTEST(R)-SP SYSTEM

Sulfamethazine-spiked chicken liver and kidney were tested for residue s using the Delvotest SP. The results were compared to a standard plat e assay using Bacillus subtilis as the test organism. The Delvotest SP gave positive responses to all homogenized liver replicates spiked wi th sulfamethazine at or above 1.0 mu g/g of liver. Mixed responses wer e obtained at 0.5 mu g/g and negative responses at less than or equal to 0.25 mu g/g. The plate assay had a minimum sulfamethazine detection limit of 1 mu g/g and 0.5 mu g/g of liver and kidney, respectively. C hickens were dosed with sulfamethazine (100 mg/kg of body weight) dail y for 5 days, and tissues were tested for residues after treatment sto pped. The Delvotest SP was positive for all serum and kidney samples f rom the end of treatment to 24 h, and for muscle and liver samples up to 8 h. The plate assay detected the drug up to 24 h in serum and kidn ey samples and up to 8 h in liver and muscle samples. Kidney and serum samples both appeared to be good tissues for testing sulfamethazine r esidues in chickens. Serum could be used for antemortem screening, whe reas kidney samples would appear to be the best for postmortem screeni ng of residues in chickens.