鲣肝脏水解物对大鼠脂肪代谢的影响

The effect of the hydrolyte of Katsuwonus pelamis liver on lipid metabolism in rats

研究鲣肝脏水解物对大鼠脂肪代谢的影响,以提高低值水产品废弃物的利用价值。采用高果糖饲料饲喂SD大鼠,建立高血脂大鼠模型,实验组大鼠饲料中分别添加5%和10%鲣肝脏酶解物(KPLH)。分别测定大鼠血清甘油三酯、胆固醇、高密度脂蛋白、游离脂肪酸浓度。同时还测定了肝脏甘油三酯、胆固醇、磷脂浓度以及肝脏脂肪代谢相关酶(G6PDH,ME,FAS,CPT)活性。结果显示,5%和10%KPLH添加均不同程度地明显降低大鼠血清TG浓度(P<0.05),增加血清高密度脂蛋白浓度(P<0.05),降低动脉硬化指数(P<0.01),降低肝脏TG浓度(P<0.001)。5%KPLH明显降低大鼠肝脏ME,G6PDH和FAS活性(P<0.05、P<0.01和P<0.05)。鲣肝脏水解物具有降血脂,抗动脉硬化以及预防脂肪肝的作用。

In order to utilize the waste effectively in Katsuwonus pelamis processing, we studied the effects of the enzymatic hydrolyte of Katsuwonus pelamis liver （KPLH） on lipid metabolism in rats. Fresh Katsuwonus pelamis liver was homogenized and auto-enzymatic hydrolyzed at 25 ℃ for 12 hours. After percolation, the enzymatic hydrolyte of Katsuwonus pelamis liver was freeze-dried. The male SD rats were fed high fructose basic diet （AIN 76） for 1 week. Then rats were randomly divided into 3 groups and fed 5% or 10% freezedried KPLH containing high fructose basic diet（ KPLH group）or high fructose basic diet （control group）. After 4 weeks, serum triglyceride （ TG ）, total cholesterol （ TC ）, high density lipoprotein cholesterol （HDL-C）, free fatty acid （NEFA） levels, and hepatic lipid concentrations （TG, TC） were determined. To resolve the mechanism of lipids lowing effect of KPLH in rats, the activities of key enzymes related in lipids metabolism, malic enzyme （ME）, glucose-6-phosphate dehydrogenase （G6PDH）, fatty acid synthase （FAS） and carnitin palmitoyl transferase （CPT） were determined. After 4 weeks feeding, KPLH did not affect the food intake, body weight gain, liver weight in rats. The abdominal white adipose tissue weights were lower in KPLH group compared with the control group （no statistical difference, P 〉0.05）. The serum TG levels and atherogenic index （AI） were significantly decreased in KPLH group compared with the control group （P 〈0.05, P 〈0.01 ）, and the serum HDL-C levels were significantly up-regulated by KPLH （ P 〈 0.05 ）. The concentration of serum total cholesterol was lower in KPLH group than that in control group, but there was no significant difference between KPLH group and control group （P 〉 0.05 ）. On the other hand, KPLH did not alter serum glucose and NEFA levels in rats. Those results showed that the enzymatic hydrolyte of Katsuwonus pelamis liver is beneficial to prevent hyperlipidemia and artheroschlerosis. In liver, KPLH decreased significantly the TG concentration （P 〈0.001 ） but not total cholesterol and phospholipids levels. Furthermore, the activities of G6PDH, ME and FAS were decreased by 5% KPLH in liver （P 〈0.05, P 〈0.01 and P 〈0.05）. On the other hand, KPLH did not alter the activity of CPT in liver. These suggested that the serum lipids lowing effect of KPLH is related to the down-regulation of hepatic fatty acid synthesis. This study indicated that the KPLH has anti-atherogenic and antifatty liver effects by reduced hepatic fatty acid sytnhesis.