Dietary supplementation with raw potato starch enhanced tibia mass of meat ducks potentially linked to intestine-derived inflammation.

Gait problems in poultry is a welfare issue with a prevalence of about 21% in commercial meat ducks, which compromises growth performance by restricting access to feed and water. This study evaluated the effects of raw potato starch (RPS) on intestinal barrier function and bone metabolism in both healthy and enteritis-affected meat ducks. Initial characterization revealed that RPS consists of round or oval granules with a polygonal B-type crystalline structure, exhibiting a nitrogen-corrected apparent metabolizable energy of 2.67 kcal/g for 21-d-old meat ducks. A total of 288 one-day-old male ducklings (initial body weight was 51.4 ± 1.7 g) were assigned to four groups (six replicates per group with 12 birds each) and fed diets containing 0, 6%, 12%, or 18% RPS until d 21. Dietary RPS supplementation dose-dependently (P L inear and P Quadratic < 0.05) increased tibia ash content and strength while reducing serum D-lactate content and systemic inflammation in 21-d-old ducks. Broken-line analysis identified 12% RPS as the optimal inclusion level for improving bone properties and minimizing D-lactate content. To further investigate the relationship between RPS, intestinal inflammation, and bone metabolism, an enteritis model was established using dextran sodium sulphate (DSS). A total of 288 ducklings (47.8 ± 0.8 g) were allocated to three groups until d 21: a basal diet (Ctrl), and two groups orally administered DSS at 1.2 g/(bird·d) from d 14 and fed either the basal diet (DSS) or the 12% RPS diet (DSS + RPS). Each group had 8 replicates with 12 birds each. The administration of DSS induced higher interleukin (IL)- 6 and tumour necrosis factor alpha (TNF-α) levels in both serum and bone marrow, which were accompanied by increased serum C-terminal cross-linked telopeptide of type I collagen and osteoclast frequencies in tibia, resulting in decreased tibia density (P = 0.002) and mechanical properties. Dietary 12% RPS intervention increased the content of fluorescein isothiocyanate dextran in serum (P = 0.002), a biomarker of gut leak, and reduced the TNF-α and IL-6 levels in ileum of DSS-treated ducks. Additionally, RPS supplementation altered the gut microbiota by increasing Firmicutes (P = 0.026), decreasing Bacteroidetes (P = 0.017), and enhancing the production of short-chain fatty acids (acetic acid and butyric acid, P < 0.05). Consequently, RPS improved tibia microstructure and strength in DSS-exposed birds. These benefits were associated with reduced osteoclast activity, lower osteoclast numbers, and elevated serum phosphorus contents.