Cyrtocarpa edulis fruit and its immunostimulant effect on Almaco Jack Seriola rivoliana: in vitro, in vivo and ex vivo studies.

The present study investigates for the first time chemical, proximate analyses and immunostimulant effect of Cyrtocarpa edulis fruit (CeF). Three design experiments were carried out to evaluate immunostimulant effect of C. edulis fruit: in vitro, in vivo and ex vivo studies in juveniles Almaco jack Seriola rivoliana. In general, nutraceutical studies performed by gas chromatography/mass spectrometry (GC-MS) in CeF revealed a major quantity of the carbohydrate groups and phytosterols such as β-sitosterol. Their phytochemical and antioxidant values exposed a significant content of total phenols, flavonoids, and tannins, showing an antioxidant capacity against hydroxyl and superoxide radical. The in vitro results confirm that CeF is edible and enhanced the innate immune response in head-kidney leukocytes after 24 h of immunostimulation. The in vivo results showed that myeloperoxidase, nitric oxide production, as well as antioxidant enzymes were enhanced in skin mucus of those fish fed with CeF. Interestingly in the intestine, IL-β, TNF-α, MARCO and Piscidin gene expression were up-regulated in fish fed with C. edulis after 4 weeks. Finally, ex vivo experiments showed an important enhancement on cellular parameters (phagocytosis, respiratory burst, myeloperoxidase, and nitric oxide production) in head-kidney leukocytes of fish fed CeF and intraperitoneally infected with A. hydrophila. The results demonstrate that C. edulis fruit (0.5%) represents an available phytochemical and antioxidant rich alternative with great potential as fish immunostimulant additive.