The current study investigated the effects of dietary curcumin nanoparticles (C-NPs) on the performance, hemato-biochemical profile, digestive enzymes activities, antioxidant status, humoral immunity, and liver and intestinal histology of Nile tilapia (Oreochromis niloticus). Fish (4.3 ± 0.5 g) were fed with diets enriched with 0.0 (control), 15, 30, 45, and 60 mg C-NPs/kg diet up to apparent satiety thrice a day for 60 days. The growth-stimulating effects of dietary C-NPs were significantly observed in terms of final weight, weight gain %, specific growth rate, and feed intake. Compared with the control group, serum amylase, lipase, and proteases activities of Nile tilapia significantly (P < 0.05) increased alongside the increase in dietary levels of C-NPs in a dose-dependent manner. The counts of red blood cells and white blood cells as well as hemoglobin and hematocrit levels of Nile tilapia fed with 30–60 mg C-NPs/kg diet were statistically (P < 0.05) higher than fish in the control group with no significant differences among them (P > 0.05). Moreover, lymphocytes and monocytes significantly (P > 0.05) increased; meanwhile neutrophils significantly (P > 0.05) decreased as C-NPs levels in diets increased. In a similar trend, antioxidant (malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase) and humoral immunity (lysozyme and total immunoglobulin) biomarkers were significantly higher in C-NPs-fed fish. Liver histology showed improvements in the cell architecture of fish fed with C-NPs containing diets up to 45 mg/kg diet. Compared with the control diet, feeding Nile tilapia with C-NPs diets resulted in a higher villi length/width and absorption area. According to the regression curves, the current study recommends using the dietary C-NP with optimum values of 45–55 mg/kg diet to improve the performance, digestive enzymes, antioxidant activities, and immunity response of Nile tilapia.

The study aims to investigate the potential effect of nanocurcumin as feed additive in the diet of Oreochromis niloticus to improve its growth performance, health status and resistance against Aspergillus flavus. The control group was fed on a basal diet without nanocurcumin, and four diets T1, T2, T3 and T4 were supplemented with 10, 25, 40 and 55 mg/kg of nanocurcumin, respectively, in triplicate (20 fish/replicate). The duration of the feeding trial was 60 days. The final body weight, weight gain, specific growth rate and survival rate showed significantly (p < 0.05) increased values in the nanocurcumin groups than the control. Fish fed with nanocurcumin supplementation showed improvement in RBCs, haemoglobin, total protein, albumin and globulin while there was a decrease in the liver enzymes (AST and ALT), glucose and alkaline phosphatase. The creatinine was also decreased in fish fed nanocurcumin. The digestive enzymes amylase and lipase increased in the nanocurcumin‐treated groups, and the triglycerides values showed non‐significant increase, whereas the cholesterol values showed non‐significant decrease in T1 and T4. Meanwhile, the cortisol was nearly the same in all groups. At the end of the trial, the fish were challenged with Aspergillus flavus for 15 days. Aspergillus flavus resulted in the mortality of 100% of the control group and the groups with lower doses of nanocurcumin (T1 and T2) within the first week and second week post challenge respectively. In the treatments with high doses (T3 and T4), higher survival rates were recorded in a dose‐dependent manner. The pathogenicity of Aspergillus flavus was confirmed histopathologically. It was concluded that the dietary supplementation of nanocurcumin enhanced the health status of O. niloticus by improving the haemato‐immunological response and body composition parameters of the fish, and protected it from the Aspergillus flavus infection with optimum inclusion levels of 25–40 mg/kg diet.