The objective of this study was to evaluate the effects of dietary supplementation with different doses of Curcuma longa hydrolate on the hematological, immunological and zootechnical parameters of Nile tilapia cultivated in a recirculation system (RAS). Nile tilapia (Oreochromis niloticus) were used, distributed in 16 polyethylene boxes, divided into four treatments: 0.0%; 2.5%; 7.5% and 10.0% of Curcuma longa hydrolate, in quadruplicate. After 45 days of treatment, four fish per experimental unit were anesthetized to remove blood aliquot for hematological and immunological analyzes and dissect the liver to evaluate the hepatosomatic index and final biometry. In the haematological analysis, the fish fed with 2.5% had a higher number of leukocytes, monocytes and lymphocytes than control, while the doses of 7.5% and 10.0% did not differ. Antimicrobial activity showed a significant decrease as the dose of C. longa hydrolate increased. The other hematological, immunological, hepatosomatic index and zootechnical data did not differ between treatments. Thus, supplementation of the hydrolate of Curcuma longa at a dosage of 2.5%, improved and maintained blood-immune homeostasis parameters in these animals, being suggested for further studies.