Turmeric essential oil had been used in different experiments to study for its beneficial pharmacological and nutritional effect. However , its precise mechanisms as a medicinal herb in fish regarding dose and duration of application in fish diet still need much investigation. This study was carried out to investigate the effect of dietary supplementation of turmeric on immunity, antioxidant activity, and cytokines gene expression in head kidney of Orechromis niloticus . A total of 120 apparently healthy (55±0.52 gram) Orechromis niloticus were fed on diet supplemented with (0.5% and 1% turmeric essential oil /kg diet) for 15 and 30 days. Serum biochemical parameters including, serum protein fractionation , kidney and liver functional activity, immunological and antioxidant parameters, and the expression of IL-8 , IL-1β and TGF-β were determined. The results showed that serum creatinine, serum liver transaminase (GOT), nitric oxide and lipid peroxides were significantly decreased in a concentration - dependent manner. While, serum globulins, lysoszyme activity, respiratory burst activity, hematocrit value, cytokines gene expression, total antioxidant capacity and plasma catalase were increased in time- and concentration-dependent manners. In conclusion, the results of the present study demonstrate the immunomodulatory and antioxidant roles of turmeric essential oil, which in turn improve the immune response of Nile tilapia.
Key words: Turmeric essential oil, Nile tilapia, immune response, antioxidant.