Citrullus colocynthis extract and synthesized Selenium nanoparticles enhance non-specific response and resistance against Aeromonas sobria in Nile tilapia (Oreochromis niloticus )

The effects of Citrullus colocynthis extract (CCE) and synthesized Se nanoparticles (Nano-Se) on non-specific immune response and resistance to Aeromonas sobria in Nile tilapia (Oreochromis niloticus) were investigated. Treatments included three levels of Nano-Se (0.5, 1 and 2 mg/kg of feed), three levels of CCE (0.1%, 0.3% and 0.5%) and control group (no additives). The diets were fed for 4 weeks, and biochemical indices, serum lysozyme, respiratory burst activities and antioxidant enzymes were measured on weeks 1, 2 and 4. After 4 weeks of feeding, fish were infected with A. sobria and mortalities were recorded for 14 days. Results of this study showed that feeding tilapia with CCE and Nano-Se supplements significantly enhanced biochemical indices, serum lysozymes and respiratory burst. CCE treatments had a moderate effect on superoxide dismutase and no effect on the other antioxidant enzymes. Nano-Se treatments had significantly positive effects on antioxidant enzymes. Both CCE and Nano-Se supplements reduced mortality following A. sobria infection. The lowest mortality (13%) was observed in the group fed with 2 mg/kg Nano-Se, and the highest mortality of 90% was observed in the control group. It can be concluded that C. colocynthis extract and synthesized Nano-Se supplementation added to fish feed can act as immunostimulants and enhance the immune functionality, antioxidant status and disease resistance in cultured Nile tilapia (O. niloticus).

Automated summary

The supplementation of CCE and Nano-Se significantly enhanced the immune response and resistance to A. sobria in Nile tilapia. Furthermore, Nano-Se had a more pronounced effect on antioxidant enzymes compared to CCE.