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Chapter 2,210

Residues of doxycycline and oxytetracycline in eggs after medication via drinking water to laying hens

Yoshimura, H.; Osawa, N.; Rasa, F.S.; Hermawati, D.; Werdiningsih, S.; Isriyanthi, N.M.; Sugimori, T.

Food Additives and Contaminants 8(1): 65-69

1991


ISSN/ISBN: 0265-203X
PMID: 2015932
DOI: 10.1080/02652039109373956
Accession: 002209064

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.

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