Residue Depletion of Enrofloxacin and Doxycycline in Eggs of Chinese White-Feathered Quail After Administration via Drinking Water.

The objective of this study was to examine the depletion kinetics of enrofloxacin and doxycycline in quail eggs and develop suitable withdrawal times. Four hundred healthy laying Chinese White-feathered quails were randomly assigned to five groups (n = 80 each): a control group and two dose groups (high and low) for each drug. The doses were set at the maximum dose recommended for chickens and at half of that dose, according to the Chinese Veterinary Pharmacopeia. Both drugs were administered continuously for 5 days via drinking water. Eggs were collected at different time points during the administration period and after withdrawal, until residues fell below the detection limit. During the administration period, residues in quail eggs increased progressively, with the highest accumulation found in albumen. After drug withdrawal, the elimination patterns were similar across the dose levels. Residues in albumen declined more rapidly than in yolk. For both drugs, residue concentrations declined rapidly during the initial period after withdrawal and more slowly thereafter. Using the whole-egg residue data and the Chinese national standard (GB 31650.1-2022) maximum residue limits (MRLs) of 10 µg/kg, the withdrawal times were calculated as follows: for enrofloxacin, 10.75 days (0.15 g/L) and 9.03 days (0.075 g/L); for doxycycline, 25.56 days (0.3 g/L) and 21.30 days (0.15 g/L). These results provide valuable data for residue monitoring and risk management, and offer a scientific reference for food safety assurance of quail eggs.