甘草提取物对滩羊肝脏脂肪代谢关键酶活性的影响

基于本课题组前期研究发现甘草提取物有降低滩羊皮下脂肪沉积的趋势,本试验为研究甘草提取物对脂肪代谢中枢组织——肝脏脂肪代谢关键酶活性的影响,选择日龄与体重相近的滩羊公羔50只,随机分为5组,每组10只,基础日粮中甘草提取物添加水平分别为0、1 000、2 000、3 000和4 000 mg/kg.120 d后试验羊屠宰,测定肝脏甘油三酯(TG)和总胆固醇(TC)含量,脂肪酸合成酶(FAS)、还原型辅酶Ⅱ(NADPH)生成酶、肝脂酶(HL)、脂蛋白脂酶(LPL)和总脂酶(TL)活性.结果表明,甘草提取物显著降低了肝脏TG含量(P＜0.05),添加水平在1 000、2 000、3 000和4 000 mg/kg基础日粮时,与对照组(0 mg/kg)相比分别下降了28.3％、45.5％、44.0％及40.8％；同时甘草提取物显著提高了分解酶(HL、LPL和TL)活性(P＜0.05),对TC含量、FAS及NADPH生成酶活性的影响未达到显著水平(P＞0.05).据此推测,甘草提取物主要通过调节脂肪氧化途径的关键酶活性来抑制滩羊肝脏内脂肪的沉积,进而减少肝脏内脂肪向外周组织的转运,达到降低皮下脂肪沉积的作用.

Effects of licorice extract on the activities of key enzymes in liver lipid metabolism of Tan sheep

We had revealed that licorice extract had a tendency of reducing subcutaneous fat accumulation of Tan sheep from previous research.In this study,we managed the experiment to investigate the effects of licorice extract on the activities of key lipid metabolism enzymes in liver,the central organization of lipid metabolism.Fifty male Tan lambs with similar ages and body weights were randomly divided into five groups (N=10).The supplement level of licorice extract were 0,1 000,2 000,3 000,4 000 mg/kg in basal diet respectively.The sheep were slaughtered after 120 days,and the liver triglycerides (TG),total cholesterol (TC),fatty acid synthase (FAS),NADPH generating enzymes,hepatic lipase (HL),lipoprotein lipase (LPL) and total lipase (TL) were tested.The results showed that the liver TG level was reduced significantly (P< 0.05),and decreased by 28.3%,45.5%,44.0% and 40.8% respectively for the level of licorice extract 1 000,2 000,3 000,4 000 mg/kg in basal diet compared with the control group (0 mg/kg),and the lipolytic enzymes (HL,LPL,TL) level were enhanced significantly (P<0.05).The TC level,FAS and NADPH generating enzymes activities were not significant (P >0.05).It is concluded that the function of licorice extract that suppressing lipid accumulation in the liver of Tan sheep is mainly by regulating the activities of key enzymes related to the pathway of fatty acid oxidation,thereby reducing the transport of fat from liver to peripheral tissue,and ultimately achieving the effect of reducing subcutaneous fat accumulation.