Effects of dietary tannic acid and antimicrobial peptide on growth performance, immune response, antioxidant capacity, and cecal microbiota in White Pekin ducks up to 21 days of age.

Appropriate feed additives can improve animal health, promote growth, and increase economic efficiency. This study examined the effects of 0.1% tannic acid (TA), 0.02% antimicrobial peptide (AP), and their combination on the growth, immunity, antioxidant capacity, and cecal microbiota of White Pekin ducks. A total of 336 one-day-old ducks were randomly assigned to 4 dietary treatment groups (6 replicates/group, 14 ducks/replicate) for a 21-day experiment: control, 0.1% TA, 0.02% AP, and 0.1% TA + 0.02% AP. Over the 1-21 day period, 0.02% AP increased average daily feed intake (ADFI) and 0.1% TA decreased feed conversion ratio (FCR) compared with the control (P < 0.05). Serum immunoglobulin and complement levels, antioxidant enzyme activities, and total antioxidant capacity were increased, and MDA content was decreased in both the 0.1% TA and 0.02% AP groups (P < 0.05). Some of these improvements were also observed in the 0.1% TA + 0.02% AP group. Cecal Actinobacteria abundance was lower in all treatment groups than in the control (P < 0.05). However, no synergistic effect was observed between 0.1% TA and 0.02% AP on growth performance, serum parameters, or microbiota composition. In summary, dietary 0.1% TA can improve FCR and 0.02% AP can increase ADFI in White Pekin ducks during the first 21 days post-hatching. Individual supplementation with either additive can enhance antioxidant capacity and immune function and reduce cecal Actinobacteria abundance.