Application of Branched-Chain Amino Acids Mitigates Mitochondrial Damage to Spotted Seabass (Lateolabrax maculatus) Hepatocytes Cultured in High-Glucose and High-Fat Media

Simple Summary: Mitochondria are central to cellular metabolism, energy production, and overall cell viability. In aquaculture, high-glucose or high-fat diets can induce oxidative stress, disrupt metabolic homeostasis, and impair mitochondrial function. Branched-chain amino acids (BCAAs), essential for animal growth, exhibit diverse biological benefits, including metabolic regulation and mitochondrial protection. This study demonstrated that BCAAs supplementation enhances mitochondrial function in hepatocytes of spotted seabass (Lateolabrax maculatus), effectively mitigating oxidative stress and cellular damage induced by excessive glucose or lipid exposure. This study explored the metabolic effects of branched-chain amino acids (BCAAs) on the hepatocytes of spotted seabass (Lateolabrax maculatus) under high-glucose (HG) or high-fat (HF) conditions. Hepatocytes were cultured under five different conditions: control, high glucose (HG), HG + BCAAs (Leu 0.8 mM, Ile 0.4 mM, Val 0.8 mM), high fat (HF), and HF + BCAAs (Leu 0.8 mM, Ile 0.8 mM, Val 0.8 mM). After 72 h of culture, cells and cell supernatants were collected to measure relevant indicators. The results revealed that BCAAs supplementation significantly reduced glycogen and lipid accumulation in hepatocytes exposed to HG or HF conditions (p < 0.05). Additionally, alanine aminotransferase and aspartate aminotransferase activities in the supernatant were significantly decreased, indicating that BCAAs supplementation alleviated hepatocyte damage induced by these conditions. Furthermore, BCAAs addition markedly enhanced antioxidant defense by increasing superoxide dismutase and catalase activities, improving total antioxidant capacity, and reducing malondialdehyde levels. Metabolic enzyme activity analysis revealed that BCAAs significantly increased the activities of citrate synthase (CS), alpha-ketoglutarate dehydrogenase complex (alpha-KGDHC), succinate dehydrogenase (SDH), phosphoenolpyruvate carboxykinase (PEPCK), and liver pyruvate kinase (LPS), while significantly decreasing fatty acid synthase (FAS) activity. Gene expression analysis further demonstrated that BCAAs supplementation downregulated the expression of lipogenic genes (fas and srebp-1c) and upregulated the expression of lipolytic genes (ppa alpha and atgl) and glucose metabolism-related genes (g6pd, hk, pfk, pk, fbp, and g6pase). Under HG or HF conditions, hepatocytes exhibited decreased adenosine triphosphate (ATP) content, increased reactive oxygen species (ROS) levels, and reduced mitochondrial membrane potential. These adverse effects were mitigated by BCAAs supplementation. In conclusion, BCAAs supplementation alleviated hepatocyte damage caused by HG or HF conditions, enhanced antioxidant defenses, and protected mitochondrial activity and function by promoting glucose and lipid metabolism.