Disposition kinetics and tissue residues of Lincomycin following intravenous, intramuscular and single and multiple oral dosing in domestic geese ( <i>Anser anser domesticus</i> )

1. Lincomycin, a lincosamide antibiotic, is commonly used for treating necrotic enteritis and chronic respiratory disease caused by avian mycoplasmas. Given its similar use in other birds, it has the potential to be applied off-label in geese. 2. This study examined the pharmacokinetics and tissue residues of Lincomycin in 16 healthy adult male geese. The study consisted of four phases, each separated by a one-month 'washout' period. Geese received Lincomycin <i>via</i> intravenous (IV, 1 mg/kg), single intramuscular (IM, 15 mg/kg), single oral (PO, 50 mg/kg) and multiple oral (SID, 5 mg/kg for 7 d consecutively) routes. Blood and tissue samples were collected at specific intervals for analysis using a validated UHPLC-MS/MS method. 3. Following IV administration, the mean values t1/2, V_d, and Cl were at 4.19 h, 2727.16 ml/kg, and 451.26 ml/h/kg, respectively. For both extravascular routes, Lincomycin displayed a high bioavailability (109% IM; 95% single PO) and rapid absorption (MAT 0.42 h IM; 2 h single PO) in geese. Multiple oral doses showed no plasma accumulation, but tissue data revealed quantifiable concentrations at 72 h. The calculated preliminary WT were determined as 1 d for the muscles, and 4 d for the kidneys and liver. 4. Despite the promising PK profile, the administered doses were inadequate to sustain drug concentrations above the MIC₉₀ for certain target pathogens, indicating the need for further optimisation of treatment regimens, including combinations with spectinomycin, as practiced in other animal species.