本研究旨在评估草甲酸钠(SO)降低乳酸产量对生长性能的影响,饲喂高碳水化合物(CHO)饮食的小虫的乳酸,葡萄糖和脂质代谢以及葡萄糖耐量。体外研究,原代肝细胞在对照培养基(5.5mM葡萄糖)中孵育48小时,高葡萄糖培养基(25mM葡萄糖,HG)或含硫高葡萄糖培养基(25mM葡萄糖50mMSO,HG-SO)。结果显示乳酸和甘油三酯(TG)水平,HG-SO组的乳酸脱氢酶a(LDH-a)表达明显低于HG组。体内研究,M.salmoides(5.23±0.03g)饲喂四种含有对照饮食(10%CHO,C),和三个SO含量(0(HC),分别为100(HC-SO1)和200(HC-SO2)mgkg-1)的高CHO饮食(20%CHO),持续11周。高CHO饮食显着降低体重增加率(WGR),比增长率(SGR),p-AMPK/t-AMPK比值,胰岛素受体底物1(IRS1)的表达,胰岛素样生长因子I(IGF-I),胰岛素样生长因子I受体(IGF-IR),果糖-1,6-双磷酸酶(FBPase),过氧化物酶体增殖物激活受体α(PPARα)和肉碱棕榈酰转移酶1α(CPT1α)与C组相比,而血浆葡萄糖水平则相反,TG和乳酸,组织糖原和脂质含量,和LDH-a的表达,单羧酸转运蛋白1和4(MCT1和MCT4),胰岛素,葡萄糖激酶(GK),丙酮酸脱氢酶E1亚基(PDH),甾醇调节元件结合蛋白1(SREBP1),脂肪酸合成酶(FAS)。HC-SO2饮食显着增加WGR,SGR,p-AMPK/t-AMPK比值,和IRS1,IGF-I的表达,IGF-IR,GK,PDHα,PDHβ,FAS,乙酰辅酶A羧化酶1(ACC1),PPARα和CPT1α与HC组比较。此外,HC-SO2饮食还增强了葡萄糖负荷后鱼的葡萄糖耐量。总的来说,通过提高糖酵解,SO减少的乳酸产量有利于高CHO饲喂的M.salmoides的生长性能和葡萄糖稳态,脂肪生成和脂肪酸β-氧化以及糖原生成和糖异生的抑制。
The study was performed to evaluate the effects of the reduced lactate production by sodium oxamate (SO) on growth performance, lactate and glucose and lipid metabolism, and glucose tolerance of Micropterus salmoides fed high-carbohydrate (CHO) diets. In in vitro study, primary hepatocytes were incubated for 48 h in a control medium (5.5 mM glucose), a high-glucose medium (25 mM glucose, HG), or a SO-containing high-glucose medium (25 mM glucose + 50 mM SO, HG-SO). Results indicated lactate and triglyceride (TG) levels, and lactate dehydrogenase a (LDH-a) expression in the HG-SO group were remarkably lower than those of the HG group. In in vivo study, M. salmoides (5.23 ± 0.03 g) were fed four diets containing a control diet (10% CHO, C) and three SO contents [0 (HC), 100 (HC-SO1), and 200 (HC-SO2) mg·kg-1, respectively] of high-CHO diets (20% CHO) for 11 wk. High-CHO diets significantly reduced weight gain rate (WGR), specific growth rate (SGR), p-AMPK-to-t-AMPK ratio, and expression of insulin receptor substrate 1 (IRS1), insulin-like growth factor I (IGF-I), insulin-like growth factor I receptor (IGF-IR), fructose-1,6-biphosphatase (FBPase), peroxisome proliferator-activated receptor α (PPARα), and carnitine palmitoyl transferase 1α (CPT1α) compared with the C group, whereas the opposite was true for plasma levels of glucose, TG, lactate, tissue glycogen, and lipid contents, and expression of LDH-a, monocarboxylate transporter 1 and 4 (MCT1 and MCT4), insulin, glucokinase (GK), pyruvate dehydrogenase E1 subunit (PDH), sterol-regulatory element-binding protein 1 (SREBP1), fatty acid synthase (FAS). The HC-SO2 diets remarkably increased WGR, SGR, p-AMPK-to-t-AMPK ratio, and expression of IRS1, IGF-I, IGF-IR, GK, PDHα, PDHβ, FAS, acetyl-CoA carboxylase 1 (ACC1), PPARα, and CPT1α compared with the HC group. Besides, HC-SO2 diets also enhanced glucose tolerance of fish after a glucose loading. Overall, the reduced lactate production by SO benefits growth performance and glucose homeostasis of high-CHO-fed M. salmoides through the enhancement of glycolysis, lipogenesis, and fatty acid β-oxidation coupled with the suppression of glycogenesis and gluconeogenesis.