Effects of dietary barberry root powder on growth performance, immune responses, antioxidant status, and antioxidant-related gene expression in grass carp (Ctenopharyngodon idella).

Due to having positive effects on aquaculture, plant-based dietary is very important. Therefore, this research examined the barberry root powder (BRP) supplementation on various parameters including growth performance, blood characteristics, antioxidant activity, gene expression related to antioxidant activity, and antibacterial properties in juvenile grass carp. The carps (mean weight 9 ± 0.58 g) were divided into 4 groups (a control group and three treatment groups receiving 0.5%, 1%, and 2% BRP), and the experiment duration was for 56 days. The results indicated no significant differences in growth metrics among the treatment groups consuming diets with varying BRP concentrations. However, blood analysis revealed significant variations in white blood cell counts in fish that received BRP. After the feeding period, serum lysozyme activity and alkaline phosphatase activities in fish were significantly elevated in the BRP-fed groups compared to the controls. In contrast, activities of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase were notably lower in the BRP-fed groups. Additionally, the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), and malondialdehyde in blood serum were significantly increased in fish that consumed BRP-enriched diets. Enhanced expression of mRNA for CAT, GPX, and SOD enzymes was observed in the gills, liver, and kidneys of BRP-fed fish. Furthermore, dietary BRP supplementation significantly improved survival rates (up to 90% in the 2% BRP group) following a challenge with Aeromonas hydrophila. These findings indicate that BRP supplementation, particularly at 1-2% levels, may positively influence certain immune functions, antioxidant status, and disease resistance in juvenile grass carp.