LAUSR

Abstract Filamentous microalga Tribonema sp. contains multiple bioactive compounds, such as eicosapentaenoic acid (EPA), palmitoleic acid and chrysolaminarin. Tribonema sp. is potentially a nature and safe ingredient in aquatic feed. Therefore, 6-week feeding experiment was conducted to investigate the effects of Tribonema sp. on growth performance, antioxidant capacity, immunity and hepatic health of Trachinotus ovatus. Three isonitrogenous and isolipidic diets (TS0, TS1 and TS5) containing 0% (control group), 1% and 5% Tribonema sp. were formulated, respectively. Results indicated that T. ovatus fed with TS5 diet significantly improved the growth performance by enhancing digestive enzyme activities and up-regulating the expression of growth hormone (GH) and insulin-like growth factor (IGF-I). T. ovatus fed with TS5 diet also significantly facilitated the antioxidant capacity through activating the Nrf2-ARE signal pathway and increasing antioxidant enzyme activities. Meanwhile, TS5 diet significantly promoted liver health by upregulating the expression of anti-inflammatory cytokines and downregulating the expression of pro-inflammatory cytokines. Furthermore, TS5 diet also upregulated the expression levels of non-specific immune related genes, including complement 4 (C4), c-type lysozyme (C-Lyz) and heat shock protein 70 (HSP70). In conclusion, Tribonema sp. can be used as feed ingredients to increase growth performance, antioxidant capacity, immunity and improve hepatic health in T. ovatus.