Effects of α-lipoic acid supplementation in a high-fat diet on growth, lipid metabolism and mitochondrial function in spotted seabass (Lateolabrax maculatus)

The aim of this study was to explore the impacts of incorporating α-lipoic acid (LA) in a high-fat diet (HFD) on growth, lipid metabolism and mitochondrial function in Lateolabrax maculatus. A normal-fat diet (NFD, 10 % lipid), a high-fat diet (HFD, 16 % lipid) and three LA-added HFD (200, 400, or 600 mg kg⁻¹ LA) were prepared and fed to five group of L. maculatus for 57 days. Supplementation of 400 mg kg⁻¹ LA to the HFD improved growth performance and feed utilization. LA treatment reduced the lipids concentration in serum and liver. Moreover, application of 400 mg kg⁻¹ LA in HFD notably decreased the activity of transaminases in serum. Liver oil red O staining results revealed the larger area of red lipid droplets in HFD group compared to the NFD group. Also, abdominal fat HE staining results showed larger adipocytes in the HFD group. Interestingly, LA application led to a reduction in the area of red lipid droplets and a decrease in the size of adipocytes. Furthermore, LA addition alleviated the HFD-induced oxidative stress as identified by enhanced mitochondrial citrate synthase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, and succinate dehydrogenase activities. Meanwhile, LA administration induced the activation of mitochondrial biogenesis, and up-regulated the expression of autophagy-related genes. In conclusion, LA incorporation into HFD for L. maculatus promoted growth performance, enhanced liver mitochondrial function, and mitigated excessive fat accumulation in the liver.