Tylvalosin pharmacokinetics, tissue residues, and withdrawal intervals following oral and intravenous administration in geese (Anser anser domesticus), domestic pigeons (Columba livia), and Japanese quail (Coturnix japonica).

The pharmacokinetics of tylvalosin, a veterinary macrolide antibiotic, were evaluated in 2 groups of geese, 26 groups of pigeons, and 26 groups of quail (n = 6 birds/group) following a single intravenous (IV) and oral therapy. Tylvalosin concentrations in plasma samples obtained at various intervals up to 48 h post-dosing were assessed employing high-performance liquid chromatography. Furthermore, 30 birds of each species were given tylvalosin orally at 25 mg/kg/day for 5 days for investigating its residues in tissues. After IV injection, tylvalosin exhibited wide distribution in the three species with volumes of distribution of 11.07 ± 1.68, 21.94, and 22.82 L/kg in geese, pigeons, and quail, respectively. After being administered once orally, the peak plasma levels were 4.51 ± 0.32, 1.53, and 0.97 µg/mL, reached at 1 h in geese, pigeons, and quail, respectively. The oral bioavailability was 87.82% in geese, 92.17% in pigeons, and 94% in quail. In the tissue depletion experiment, the highest tylvalosin residues were recorded in the lung, followed by the liver and then the muscle; meanwhile, skin and fat tissues contained the lowest levels. Tylvalosin demonstrated rapid absorption, high bioavailability, and extensive distribution in all three species after oral treatment. Based on the tissue depletion data, withdrawal times of 26 days for geese, 19 days for pigeons, and 13 days for quail are recommended to ensure food safety. Future PK/PD modeling studies are required to adjust dosage regimens of tylvalosin in clinical settings.