The positive effects of dietary <em>Rhodiola rosea</em> extract on liver glucose metabolism and antioxidant/inflammatory response in <em>Lateolabrax maculatus</em> fed high-carbohydrate diets

Abstract

This study investigated the effects of Rhodiola rosea extract supplementation on liver morphology, antioxidant capacity, inflammatory response, insulin signaling pathway, and glucose metabolism in Lateolabrax maculatus (9.37±0.14g). Three experimental diets were prepared: a control group (20% carbohydrate), a high-carbohydrate (HC) group (30% carbohydrate), and a high-carbohydrate with Rhodiola rosea extract (HCR) group (30% carbohydrate + 120 mg/kg Rhodiola rosea extract). The HC group showed significant increases in survival rate (SR), hepatosomatic index (HSI), triglyceride (TG), and liver malondialdehyde (MDA) levels, along with increased liver vacuoles, blurred cell boundaries, and larger lipid droplets. Additionally, the expression levels of Keap1, NF-κB, IKKβ, TNF-α, IL-8, IL-12p40, AKT2, SOCS3, GK, PEPCK, FBP, and GSK3β mRNA in hepatic tissue were markedly higher than in the control group (p < 0.05). Conversely, liver activities of T-AOC and CAT, and mRNA levels of CAT, HO-1, Nrf2, and TGF-β were significantly lower (p < 0.05). Compared to the HC group, the HCR group exhibited significant increases in SGR, plasma indices of INS, LA, PA, and liver enzyme activities of T-AOC and SOD (p < 0.05), as well as elevated mRNA levels of CAT, TGF-β, PI3Kα, PI3Kβ, GK, PK, and PFK in the liver (p < 0.05). Histological analysis revealed that hepatocytes in the HCR group had a higher concentration of nuclei, and the size and quantity of lipid droplets were reduced compared to the HC group. Furthermore, liver glycogen, plasma indices of TG and ALT, and liver enzyme activities of PEPCK, HK, and CAT decreased in the HCR group (p < 0.05). The expression levels of Keap1, IKKβ, IL-8, IL-12p40, NF-κB, IFN-γ2, SOCS3, TNF-α, FBP, G6Pase, and GSK3β mRNA were also reduced in the HCR group compared to the HC group (p < 0.05). In conclusion, Rhodiola rosea extract supplementation at 120 mg/kg in high-carbohydrate diets can mitigate the adverse effects of carbohydrate-rich diets on Lateolabrax maculatus by improving glucose metabolism and enhancing defenses against oxidative stress and inflammation.