LAUSR

Recently, the use of natural immunopotentiators, such as plant extracts, is predicted to offer high disease-prevention potential in aquaculture. However, few reports on the immunomodulatory impacts of olive extract (OE) on teleost are available. Therefore, the effects of dietary intake of triterpene-enriched OE on black sea bream (Acanthopagrus schlegelii) were investigated in this study. Our data showed that total blood cell counts, in vivo content of lysozyme, activities of antiprotease and myeloperoxidase, and contents of IL-4 and IL-6 were significantly up-regulated by dietary intake of triterpene-enriched OE. Additionally, the hampered immune response induced by cadmium exposure was significantly mitigated by the administration of OE as were indicated by partially or completely rescued immune-relating parameters. Furthermore, the expressions of immune-related genes encoding NF-κB inhibitor alpha (IkBα), tumor necrosis factor α (TNFα), cyclooxygenase-2 (COX-2), and proto-oncogene protein c-fos (FOS) were found to be significantly up-regulated by the dietary intake of OE. In general, the results suggested that the dietary intake of triterpene-enriched OE has immune enhancing effect in black sea bream. Such effect may be realized by 1) increasing the total counts of diverse blood cells; 2) activating nonspecific immune biomolecules; and 3) affecting signaling pathways such as IKK and ERK and subsequently inducing IL-4 and IL-6 biosyntheses.