Abstract
This study evaluated the effects of supplementing low-protein diets with Edible Dock Powder (EDP) on the growth performance, slaughter traits, serum biochemical parameters, muscle quality, and cecal microbiota of Sanhua geese. A total of 288 healthy, five-week-old Sanhua geese were randomly assigned to six dietary treatments in a 3 × 2 factorial design, with three crude protein levels (16.00 %, 14.50 %, and 13.00 %) and two levels of EDP supplementation (0 % and 2.50 %). Two-way ANOVA and Duncan's multiple range test were used for statistical analysis. EDP supplementation significantly increased average daily gain (ADG) and improved feed-to-gain ratio (F/G) during both growth phases (P<0.01). Lower protein levels significantly reduced average daily feed intake (ADFI) and increased the apparent digestibility of gross energy (ADGE) (P<0.01). EDP significantly improved slaughter rate and eviscerated yield (P<0.05), while reducing liver weight and webbed feet yield (P<0.01). Reduced protein levels decreased serum globulin (GLB) and increased blood urea nitrogen (BUN) levels (P<0.05), with significant interactions between protein levels and EDP supplementation (P<0.05). EDP also significantly altered the cecal microbiota composition, reducing the relative abundance of Actinobacteria, Megamonas, and Collinsella (P<0.05), and affecting KEGG pathways related to protein modification and secondary metabolite degradation (P<0.05). In conclusion, EDP supplementation in low-protein diets improved growth performance, slaughter characteristics, and cecal microbiota, showing potential as a sustainable feed additive for reducing environmental impact and improving the economic efficiency of poultry production.