Supplementation of Rose Petal (Rosa rubiginosa L.) as Functional Feed Additive Enhances Growth, Pigmentation, Immune Response, and Gut Health in Goldfish (Carassius auratus)

Natural additives are increasingly valued in ornamental fish aquaculture. Rose petal contains bioactive compounds, yet their effects on goldfish ( Carassius auratus ) remain underexplored. This study assessed the impacts of graded dietary rose petal supplementation (0, 5, 10, 20, and 40 g/kg; RP-0 to RP-40) over an 8-week feeding trial on growth performance, skin pigmentation, serum antioxidant status, intestinal gene expression, and gut microbiota composition. Fish fed RP-supplemented diets, particularly at 40 g/kg, exhibited significantly higher final weight and weight gain than the RP-0 group (p < 0.05), without adverse effects on survival or feed conversion ratio. Skin redness (a⁎) and yellowness (b⁎) increased significantly in a dose-dependent manner (p < 0.05 at RP-20/40 for a⁎, RP-40 for b⁎). Serum antioxidant capacity improved with increasing RP levels, as indicated by higher ABTS and SOD activities and lower MDA levels (p < 0.05). Dietary rose petal supplementation also significantly upregulated intestinal expression of antioxidant ( HSP70 , CYP1A ), growth ( IGF , TGF ), and immune ( LYZ , TNFα ) genes, primarily at 20–40 g/kg (p < 0.05). While rose petal significantly altered gut microbiota composition based on beta diversity (PERMANOVA p = 0.017) and specific taxon abundances (e.g., increased Staphylococcus at RP-40 and decreased Alloprevotella at RP-5; ANCOMBC2, q < 0.05), it did not significantly affect alpha diversity or exhibit strong correlations with host physiological parameters after FDR correction. Overall, the results of this study highlights rose petal as a natural functional additive for ornamental aquaculture.