title: Residues of doxycycline and oxytetracycline in eggs after medication via drinking water to laying hens.
abstract: Doxycycline (DOTC) and oxytetracycline (OTC) were dissolved in drinking water (0.5 g/l) and supplied to laying hens for 7 consecutive days. Eggs laid were collected daily during and after medication, and the antibiotic concentrations in the yolk and albumin were determined by the cup-plate method with Bacillus cereus var. mycoides ATCC 11778. The concentrations of both antibiotics were increased in yolk day by day with the advance in medication, reached peaks 2 days after withdrawal and then declined gradually. Mean peak concentrations in the yolk were 6.70 micrograms/g for DOTC and 1.42 micrograms/g for OTC. Peak concentrations in the albumin occurred in the middle stage of medication, where the mean values were 12.24 micrograms/g for DOTC and 1.03 micrograms/g for OTC. DOTC was detected in albumin until 24 days after withdrawal and for 2 days more in yolk than in albumin. OTC was detected in yolk until 9 days after withdrawal. The depletion period of OTC was shorter for the albumin, where the residue disappeared in all eggs 6 days after withdrawal. In spite of similarities between DOTC and OTC in structure, DOTC was deposited in higher concentrations and lasted for a longer period in eggs. This characteristic was considered due to its greater lipophilicity, closely correlated with oral absorption and tissue penetration.
authors.affiliation: Balai Pengujian Mutu dan Sertifikasi Obat Hewan (Veterinary Drug Assay Laboratory), Gunung Sindur, Bogor, Indonesia.
authors.forename: H
authors.initials: H
authors.lastname: Yoshimura
authors.forename: N
authors.initials: N
authors.lastname: Osawa
authors.forename: F S
authors.initials: FS
authors.lastname: Rasa
authors.forename: D
authors.initials: D
authors.lastname: Hermawati
authors.forename: S
authors.initials: S
authors.lastname: Werdiningsih
authors.forename: N M
authors.initials: NM
authors.lastname: Isriyanthi
authors.forename: T
authors.initials: T
authors.lastname: Sugimori
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002645:Chickens / Q000378:metabolism*; D004318:Doxycycline / Q000008:administration & dosage / Q000032:analysis*; D004326:Drinking; D004350:Drug Residues / Q000032:analysis*; D004529:Egg White / Q000032:analysis; D004530:Egg Yolk / Q000032:analysis; D004531:Eggs / Q000032:analysis*; D005260:Female; D010118:Oxytetracycline / Q000008:administration & dosage / Q000032:analysis*
chemical_list: D004318:Doxycycline; D010118:Oxytetracycline