The objective of the present study was to evaluate the effect of dietaryAnta^®Ox FlavoSyn (as a wide source of natural Proanthocyanidins) on growth performance, carcass characteristics, blood constituents, and economic efficiency of local Domyati ducklings for 7 weeks. A total of 240 ducklings (8 weeks of age) was distributed into 4 groups with 6 equal replicates (10 ducklings/each replicate). The first group was fed the control basal diet (BD, 0.0 mg Anta^®Ox FlavoSyn/kg diet) while, others fed 100, 150 and 200 mg Anta^®Ox FlavoSyn/kg diet. The obtained results illustrated that ducklings fed 100 and 150 mg Anta^®Ox FlavoSyn/kg diet displayed significantly (P ≤ 0.05) higher body weight gain, and performance index, lower feed consumption, and better feed conversion ratio than those fed the high level 200 mg/kg diet or those fed free-Anta^®Ox FlavoSyn BD (control group) at different experimental periods. Ducklings fed different levels of Anta^®Ox FlavoSyn had significantly improved carcass traits, hematological, and serum biochemical parameters, total antioxidant capacity, and economic efficiency compared to the control group. Consequently, it could be concluded that the usefulness of Anta^®Ox FlavoSyn as a promising feed additive for enhancing the productive performance, health status, physiological responses of Domyati ducklings. Owing to its low price and the high natural antioxidant properties of the tested material can be used economically in diets of growing local Domyati ducklings, especially at levels of 100 and 150 mg/kg diet.