Effects of puerarin on growth, liver immunity and antioxidant capacity of yellowfin seabream (Acanthopagrus latus) under oxidized fish oil stress

Puerarin, an isoflavone, exhibits protective effects against liver damage. This study investigated the effects of puerarin on the growth, liver immunity, and antioxidant capacity of yellowfin seabream fed with oxidized fish oil. A total of 135 yellowfin seabream (13.00 +/- 0.05 g) were randomly divided into nine tanks (15 fish per tank), and fed with three types of diets for 56 days: a normal control fed with 6 % fresh fish oil (NC), an experimental control fed with 6 % oxidized fish oil (OFO), and a treatment fed with 6 % oxidized fish oil and supplemented with 400 mg/kg puerarin (OFP). Results showed, oxidized fish oil decreased the growth of fish, caused liver damage, and suppressed the fish's immunity. Compared to the NC group, the weight gain (WG) and specific growth rate (SGR) of the fish in the OFO group were significantly reduced; the activities of superoxide dismutase (SOD) and catalase (CAT) in serum were significantly decreased; liver morphology showed loose cytoplasm with a large amount of fatty degeneration; the lysozyme (LZM) activity in serum and liver was significantly reduced. On the other hand, compared to the NC and OFO groups, the WG and SGR of fish in the OFP group were significantly improved. Additionally, compared to the OFO group, the serum SOD and liver CAT activities in the fish of the OFP group were significantly increased, and the MDA content in serum and liver was significantly reduced. The extensive fatty degeneration in the liver was alleviated. The LZM activity in the serum and liver of fish in the OFP group was significantly higher than that in the OFO group, returning to the levels of the NC group. Meanwhile, puerarin significantly enhanced the expression of Nrf2. In conclusion, puerarin alleviated the adverse reactions induced by oxidized fish oil and promoted the growth of yellowfin seabream.