Abstract
Background:
The global demand for fish and fish products has increased due to population growth and healthier food choices. However, bacterial infections caused by Aeromonas species pose a challenge. Antibiotics are crucial for disease control, but multidrug resistance is a global concern. Eco-friendly disease management methods, like saffron, have been identified as potential treatments.

Aim:
The study investigated the effects of dietary supplementation with Saffron on Nile tilapia's growth performance, immune response, and disease resistance.

Methods:
180 fish were acclimatized for two weeks and randomly allocated into three groups. The first group served as a control, while the other two groups were fed a basal diet supplemented with Saffron at 1.5 g/kg (T1) and 0.5 g/kg (T2), respectively, for 12 weeks. Biochemical blood parameters. Histopathology and immunohistochemical studies were performed on the gills, liver, and spleen tissues.

Results:
Following the feeding trial with Saffron supplement, especially at higher levels enhanced weight gain, Growth performance, plasma total protein and globulin showed higher levels in fish groups with dietary with Saffron at 1.5 g/kg ( T1) and 0.5 g/kg (T2) than in fish fed the control diet Regulate the immune response in lysozyme activity and immunoglobulin M (IgM). Regeneration of gills. liver, and spleen tissues were noticed Furthermore, saffron-treated organs exhibited immunoreactivity to TNF-α was mostly seen in the liver and gills, although it was also somewhat in the kidney and spleen and CD68, the group were challenged with Aeromonas hydrophila, improved its defences against Aeromonas hydrophila, immunity, and disease resistance than the control group.

Conclusion:
The results showed that saffron supplementation significantly increased the survival rate of fish challenged with Aeromonashydrophila. It also enhanced the immune response of fish, as evidenced by increased levels of serum immunoglobulins and lysozyme activity. These findings suggest that saffron supplementation could be a promising strategy for the prevention and treatment of bacterial infections in aquaculture.

Key words: Histopathology, Immunohistochemistry, Nile tilapia, Saffron, Aeromonas hydrophila