Modulation of growth, immunity, and immune‐antioxidant gene expression in Nile tilapia, Oreochromis niloticus, culture under biofloc system by dragon fruit, Hylocereus undatus, peel powder

Abstract This study examines the use of dragon fruit peel (DFP) powder as a dietary supplement on growth performance, immune responses, and gene expression of Nile tilapia, Oreochromis niloticus, cultured within biofloc systems. A total of 300 Nile tilapia fingerlings (14.64 ± 0.09 g) were subjected to five dietary treatments, with DFP added to a basal diet at doses of 0, 20, 40, 80, and 160 g kg−1 DFP. Growth and immunological responses were assessed after 4 and 8 weeks of feeding, and the transcriptional level of immune and antioxidant‐related genes was measured after 8 weeks. Fish fed diets containing DFP exhibited significantly greater weight gain, faster growth, and enhanced levels of key indicators of immunity than control fish (p