Dietary rutin enhances growth performance and antioxidant defense under ammonia stress in Nile tilapia (Oreochromis Niloticus).

Ammonia (Amm) accumulation is a critical challenge in intensive aquaculture systems, leading to impaired fish health, reduced productivity, and economic losses. Identifying natural, safe, and cost-effective strategies to mitigate Amm toxicity is essential for sustainable aquaculture practices. The present study was designed to investigate the protective efficacy of dietary rutin (RUT) supplementation against Amm-induced toxicity in Nile tilapia, emphasizing the antioxidant role of RUT. 120 Nile tilapia were divided into four groups as follows: control group, RUT (1 g/kg diet) group, Amm (5 mg/L water) group, and RUT + Amm group. The daily exposure of fish to Amm for four weeks significantly increased blood Amm nitrogen in fish, causing a reduction in their growth performance, behavioral changes with mortalities, oxidants/antioxidants imbalance, and an elevation of liver and kidney function biomarkers, besides severe histopathological alterations in many organs. While supplementation of the diet with RUT significantly improved both the health status of fish and the water quality parameters in the aquarium, where serum malondialdehyde and catalase levels were reduced, while the reduced glutathione level was elevated in the Amm + RUT group compared to the Amm group. Concerning the water quality parameters, RUT reduced the unionized Amm, nitrite, and nitrate levels in water compared to the Amm group. In conclusion, RUT can effectively reduce Amm toxicity in Nile tilapia and improve water quality, offering a sustainable aquaculture solution.