植物固醇奶粉改善攝食高脂飼料倉鼠之脂質代謝   全文下載

Beneficial Effects of Plant Sterols/Stanols-Containing Milk Powder on Lipid Metabolism in Hamsters

本實驗目的在探討「植物固醇奶粉（plant sterols/stanols-containing milk powder，PSmP，含有2.78%植物固醇）」對倉鼠脂質代謝之影響。七週齡之雄性倉鼠，以一般商業飼料餵養一週後淘汰體重差異過大者，於進入試驗前犧牲部分動物，採集血液及肝臟檢體；其餘動物隨機分為五組每組16 隻（兩隻飼養於同一籠中），第一組為控制組（C組），為一般老鼠飼料中添加椰子油與玉米油（1:1）之混和油，將飼料之脂肪含量提高至15%（w/w）並添加0.5%（w/w）膽固醇，使成為高脂肪高膽固醇之飼料。第二組為正控制組（PC組），於高脂肪高膽固醇飼料中添加0.72%（w/w）植物固醇（phytosterol）。其餘三組則在高脂肪高膽固醇飼料中分別添加12.95、25.90與64.75%（w/w）之植物固醇奶粉，使此高脂肪高膽固醇飼料中最終所含植物固醇分別為飼料之0.36、0.72與1.8%（w/w）。餵食四週後犧牲動物，測肝臟及血漿中之脂肪及糞便之膽固醇與植物固醇含量。結果顯示，高劑量的「植物固醇奶粉」對動物的生長並無負面影響；且本試驗的高脂肪（15%）與高膽固醇（0.5%）飼料，有效的使倉鼠達到高膽固醇血症（hypercholesterolemia）的狀態。而於此高脂飼料中添加的「植物固醇奶粉」可降低肝臟中的膽固醇與三酸甘油酯，因而減少肝臟重量，此外並可增加糞便中性固醇之排出量，使血漿總膽固醇與Hdl以外的脂蛋白膽固醇下降，並使動脈硬化指標（atherogenic index，ldl-C/Hdl-C）下降。

The effect of plant sterols/stanols-containing milk powder (phytosterol milk powder, PSMP, containing 2.78% phytosterols mixture) on lipid metabolism in hamsters was investigated. One hundred male 7-week-old Golden Syrian hamsters were given free access to regular rodent chow and water for 1 week to acclimatize. Four extremely (10%) over- and underweight hamsters were eliminated. Sixteen hamsters were killed and examined for plasma and liver lipid compositions to establish the baseline. The remaining hamster were randomly divided into 5 groups, each group of hamsters had statistically similar average body weight, but fed with different experimental diets for 4 weeks. All 5 groups of hamsters were fed with high fat, high cholesterol diet containing different ingredients. Regular rodent chow diet was supplemented with 0.5% (w/w) cholesterol and corn/coconut oil mixture (corn oil/coconut oil = 1:1) to raise the final fat content to 15% (w/w) (Group 1 - control group). Group 2 was the positive control (PC) group, which was fed with diet containing 0.72% (w/w) phytosterols (consisted of 75% β-sitosterol and 10% campesterol). Groups 3-5 were the experimental groups, of which 12.95, 25.90 or 64.75% (w/w) PSMP (1×, 2× and 5× PSMP groups) was added to the diet and the phytosterol mixture contents in these diets were 0.36, 0.72 and 1.8% (w/w), respectively. At the end of 4-week feeding period, hamsters were killed and the plasma and hepatic lipid compositions together with the fecal neutral sterol content were determined. No adverse effects of PSMP on growth and health condition in hamsters were found in this experiment. At the highest feeding dose of PSMP (64.75%, w/w), hamsters had the highest body weight gain and the lowest plasma and liver lipid contents. PSMP showed significant effects on lowering the concentrations of plasma total cholesterol and low density lipoprotein cholesterol. It could also lower the atherogenic index (LDL-C/HDL-C), hepatic lipid levels and relative liver weight while raising the fecal cholesterol and phytosterols excretion in the hyperlipidemic hamsters.