Tissue-Residue Depletion of Sulfaquinoxaline in Poultry

SUMMARY Sulfaquinoxaline was administered orally to broilers, 4 to 6 weeks old, at a prophylactic dose level (0.025%) and to laying hens and cockerels at a therapeutic dose level (0.05%). Sulfonamide residues were determined in muscle, liver, kidneys, skin, and fat at 0, 3, 5, and 7 days post-treatment, as well as in eggs. Residue depletion was most rapid between 0 and 3 days after the drug was withdrawn, with faster depletion occurring in muscle and fat tissues. Residues persisted for the longest time in renal tissue. Sulfaquinoxaline concentrations in egg yolks were still extremely high 5 days after drug withdrawal. Residues were markedly greater in water-medicated chickens than in feed-medicated chickens. A withdrawal period in laying hens in excess of 7 days is necessary in order to reduce drug residues in kidney and eggs to 0.1 p.p.m.