Adaptive remodeling of lipid metabolism and antioxidant system via PPAR and Nrf2 pathways in Large yellow croaker (Larimichthys crocea) under deep-sea aquaculture vessel condition

Deep-sea aquaculture vessels have emerged as promising alternative to conventional nearshore farming, yet their physiological impacts on fish remain poorly understood. This study investigated the effects of deep-sea aquaculture vessel mode on large yellow croaker (Larimichthys crocea) over a 12-month growth trial, with land-based industrial aquaculture as the control. Results showed that no significant differences in specific growth rate (SGR) were observed for fish reared under the two aquaculture modes. While vessel-cultured large yellow croaker exhibited morphological traits more akin to wild populations, evidenced by markedly reduced condition factor (CF) and muscle lipid content. Notably, the long-chain polyunsaturated fatty acid content in muscle was significantly elevated in vessel group. Transcriptomic revealed that hepatic differentially expressed genes were consistently enriched in the process of peroxisome proliferator-activated receptor (PPAR) and unsaturated fatty acid metabolism, where down-regulated genes expression related to lipogenesis, lipid oxidation and lipid transport along with the up-regulated ones related to fatty acid elongation/desaturation were observed in vessel-cultured fish. Histologically, hepatocyte vacuolation and nuclear atrophy were alleviated in vessel-cultured fish. Additionally, aquaculture vessel induced oxidative stress, as indicated by significantly increased malondialdehyde (MDA) level in serum and liver. Concurrently, the nuclear erythroid 2-related factor 2 (Nrf2)-mediated antioxidant system tended to be activated, leading to significantly up-regulated genes expression of superoxide dismutase 1 (sod1), catalase (cat) and glutathione peroxidase (gpx) together with their enhanced enzymes activity. In conclusion, deep-sea aquaculture vessel offers a viable strategy for large yellow croaker farming. While aquaculture vessel mode could trigger lipid metabolism remodeling and oxidative stress of fish, thereby altering morphological index, flesh quality, liver health and oxidative balance.