Effects of dietary resistant potato starch inclusion and stocking density on growth performance, feather condition, and skin inflammatory cytokine gene expression in Pekin ducks.

• Dietary inclusion of 12 % resistant potato starch did not alleviate skin inflammatory response and feather growth depression caused by high stocking density (32 ducks /m2 (d 1−14); 16 ducks /m2 (d15−35)) in Pekin ducks. • Dietary resistant starch supplementation had a positive effect on the performance of ducks at normal stocking density during 1 to 14 d of age. • High stocking density had a negative effect on growth and feather performance, as well as meat deposition and even caused skin inflammation of meat duck. This study investigated whether dietary resistant potato starch (RPS) inclusion alleviated the stress response of high stocking density (HSD) based on growth performance, carcass traits, immune organ index, serum corticosterone concentration, and skin inflammatory cytokine gene expression in meat ducks. A total of 576 1-d-old male ducklings were assigned to 4 groups of 8 replicates and were under the following conditions: normal stocking density (NSD; 16 birds/m2(d 1−14); 8 birds/m2(d 15−35)) and HSD (32 birds/m2(d 1−14); 16 birds/m2(d 15−35)). The ducks were fed the basal diet or the basal diet supplemented with 12 % RPS for 35d reared under HSD and NSD to form a 2 × 2 factorial experimental design. The results showed that HSD significantly depressed (P < 0.05) the growth performance, breast meat yield, feather and spleen development, and increased (P < 0.05) the pH value in proventriculus, serum corticosterone as well as mRNA abundance of interleukin (IL)-1β and IL-6 in the skin of the pelvic back in meat ducks compared to NSD. However, dietary RPS inclusion only markedly increased (P < 0.05) BW (d 14) and BWG (d 1−14), breast meat yield, and percentage of spleen in body weight (d 35) of ducks reared under NSD. Regardless of stocking density, dietary RPS inclusion significantly increased (P < 0.05) bursa of Fabricius and spleen percentages in BW and decreased (P < 0.05) feather scoring of 35-day-old ducks in comparison with no RPS inclusion. These results suggested that HSD had a negative effect on growth and feather performance, as well as meat deposition and even caused skin inflammation of meat ducks; however, RPS supplementation did not alleviate these negative effects caused by HSD. [ABSTRACT FROM AUTHOR]