The Influence of the Dietary Lipid Level on Growth Performance, Lipid Metabolism, Oxidative Response and Hepatopancreatic Health in Macrobrachium rosenbergii

This study examined how the dietary lipid levels influence growth performance, lipid metabolism, oxidative response and hepatopancreatic health in <i>Macrobrachium rosenbergii</i>. A total of 720 post-larvae (0.86 ± 0.01 g) were divided into 4 groups according to the lipid levels in 43% protein-contained diets: 6% (L6), 8% (L8), 10% (L10), and 12% (L12). The results exhibited a significant increase in both the weight gain rate (WGR) and specific growth rate (SGR) in the L8 group (<i>p</i> < 0.05). Hepatopancreatic lipid metabolism genes (<i>fas</i>, <i>acc</i>, <i>srebp1</i>, and <i>fabp</i>) showed increased expression at higher dietary lipid levels (<i>p</i> < 0.05). The expression of <i>ampk</i> was significantly reduced, whereas the expression of <i>atgl</i> was increased in the L8 group (<i>p</i> < 0.05). Additionally, the activities of total superoxide dismutase (SOD), glutathione S-transferase (GST), and total antioxidant capacity (T-AOC) level were significantly higher in the L8 group, while the content of malondinaldehyde (MDA) was significantly reduced (<i>p</i> < 0.05). H&E staining of the hepatopancreas revealed that high-lipid diets resulted in severe hepatopancreas damage. Moreover, the L8 group exhibited consistently high cumulative survival rates under both ammonia nitrogen and high-temperature stress (<i>p</i> < 0.05). In conclusion, this study recommends a dietary lipid level of 8% to optimize growth performance in <i>M. rosenbergii</i> under high-density rearing conditions (70 prawns/m³).