Albendazole (ABZ), a benzimidazole anthelmintic, is widely used in aquaculture for parasite control. However, limited information is available on its depletion kinetics in tropical finfish. This study investigated the tissue distribution and elimination kinetics of ABZ in Genetically Improved Farmed Tilapia (GIFT) (Oreochromis niloticus) following oral dose of 10, 20, and 30 mg/kg body weight for 7 consecutive days. Tissue residues (muscle, liver, kidney) were analyzed and fitted to various kinetic models -Single First Order (SFO), Dual First Order in Parallel (DFOP), First Order Multiple Compartments (FOMC), Hockey Stick (HS)-using CAKE software to identify the best-fit model and calculate depletion half-life (DT₅₀) and 90% depletion time (DT₉₀).
In muscle, residue depletion exhibited dose-dependent kinetics. The best-fit model was DFOP for the 10 mg/kg dose (DT₅₀ = 4.9 h), SFO for 20 mg/kg (DT₅₀ = 35.4 h), and FOMC for 30 mg/kg (DT₅₀ = 23.3 h). The results indicated biphasic elimination at the low dose and multi-compartmental kinetics at higher concentrations. ABZ showed higher persistence in the kidney (DT₅₀ = 0.5–15 h) and in liver, ABZ exhibited intermediate depletion profiles. The results confirm dose-dependent, nonlinear kinetics and highlight the need for multi-model evaluation to derive accurate withdrawal periods for tilapia raised under tropical conditions.
Keywords: Albendazole, GIFT tilapia, residue depletion, CAKE modeling, DFOP, FOMC, withdrawal period