大豆蛋白对高血胆固醇模型大鼠胆固醇代谢的影响

目的:探讨膳食大豆蛋白对高胆固醇模型大鼠血浆胆固醇及其有关血脂指标的影响,并对其可能的作用机理加以研究。方法: 4周龄断乳雄性Wistar大鼠,经28d诱发高血胆固醇以后,按体重和血浆总胆固醇浓度将动物均衡分为两组,分别喂饲含酪蛋白和大豆蛋白的纯合成高脂饲料56d。结果:经28d诱导高脂模型后,高血胆固醇模型大鼠的TC浓度是阴性对照组的1 51倍。又经56d喂饲含有处理因素的饲料后,同酪蛋白组相比,大豆蛋白组动物TC,TG,apoB含量显著降低,而FT4水平显著高于酪蛋白组(P<0. 05)。膳食大豆蛋白摄入可降低高血胆固醇模型大鼠TC、TG、apoB浓度、使血浆FT4含量增高,但对HDL-C,apoA,FT3,TSH和胰岛素(INS)水平无影响。结论:大豆蛋白可影响血浆胆固醇水平,但其相应的作用机理还需进一步探讨。     

大豆蛋白及其水解物对大鼠体内胆固醇代谢的影响

[目的]探讨大豆蛋白和大豆活性肽对高胆固酵模型大鼠血浆胆固酵及其有关血脂指标的影响,并对其可能的作用机理加以研究,同时也对大豆蛋白和大豆活性肽在降低胆固醇作用方面进行初步的比较.[方法]4周龄断乳雄性Wistar大鼠,经28d诱发高血胆固醇模型以后,按血浆总胆固醇浓度将动物均衡分为3组,分别喂饲含大豆活性肽、大豆蛋白和酪蛋白的纯合成高脂饲料56d后,断头处死动物.[结果]经28d诱导高脂模型后,实验模型大鼠的TC水平为(2.01±0.26)mmol/L(n=36),阴性对照组大鼠分别为(1.33±0.20)mmol/L(n=10).高血胆固醇模型大鼠的TC浓度是阴性对照组的1.51倍(P<0.05).高血胆固醇模型大鼠又经56d喂饲含有处理因素的饲科后,酪蛋白组、大豆蛋白组和大豆活性肽组大鼠体重(g)分别增加了198.5、133.1和119.3;TC(mmol/L)水平分别为6.41±0.57、3.99±0.28和3.01±0.37;TG(mmol/L)水平分别为3.73±0.70、2.58±0.86和1.09±0.34;与酪蛋白组相比,大豆蛋白组、大豆活性肽组动物体重及TC,TG含量显著降低(P<0.05);大豆活性肽、大豆蛋白的摄入可使大鼠肝脏HMG-CoA还原酶mRNA的表达增强,而对LDL-R mRNA的表达无影响.另外,与大豆蛋白组相比,大豆活性肽组大鼠体重及TC,TG含量显著降低(P<0.05).[结论]大豆蛋白、大豆活性肽的摄入可降低高血胆固醇模型大鼠TC、TG浓度,但对HDL-C水平无显著影响;经统计学检验,大豆活性肽降低胆固醇作用与大豆蛋白相比差异有统计学意义(P<0.05).大豆活性肽、大豆蛋白可影响大鼠肝脏HMG-CoA还原酶mRNA的表达可能是其降低胆固醇的机理之一.     

大豆活性肽对大鼠体内高胆固醇代谢的影响

目的　探讨膳食大豆活性肽对高胆固醇模型大鼠血浆胆固醇及其有关血脂指标的影响 ,研究其可能的作用机制。方法　 4周龄断乳雄性Wistar大鼠 ,经 2 8d诱发高血胆固醇以后 ,按体重和血浆总胆固醇浓度将动物均衡分为 2组 ,分别喂饲含大豆活性肽和酪蛋白的纯合成高脂饲料 5 6d ,断头处死动物。实验结果用SPSS统计软件进行统计分析 (单因素F检验 )。结果　经 2 8d诱导高脂模型后 ,实验模型大鼠的TC水平为 ( 2 0 2± 0 2 7)mmol/L (n =2 1) ,而喂饲基础饲料的阴性对照组大鼠分别为 ( 1 33± 0 2 0 )mmol/L (n =9)。高血胆固醇模型大鼠的血浆总胆固醇(TC)浓度分别是阴性对照组的 1 5 1倍。又经 5 6d喂饲含有处理因素的饲料后 ,酪蛋白组和大豆活性肽组实验动物体重分别增加了 ( 198 5和 119 3) g ;TC水平分别为 ( 6 4 1± 0 5 7)和 ( 3 0 1± 0 37)mmol/L ;TG水平分别为 ( 3 73±0 70 )和 ( 1 0 9± 0 34)mmol/L ;apoB分别为 ( 0 6 2± 0 11)和 ( 0 31± 0 0 7) g/L ;FT4分别为 ( 1 0 3± 0 2 2 )和 ( 1 76±0 30 ) pmol/L ;同酪蛋白组相比 ,大豆活性肽组动物体重及TC ,TG ,apoB含量显著降低 ,而FT4水平显著高于酪蛋白组 (P <0 0 5 )。结论　膳食中大豆活性肽的摄入可降低高血胆固醇模型大鼠TC、     

大豆活性肽降低大鼠血浆胆固醇机理的初步探讨

目的探讨膳食大豆活性肽对高胆固醇模型大鼠血浆胆固醇及其有关血脂指标的影响,并对其可能的作用机理加以研究。方法4周龄断乳雄性Wistar大鼠,经28d诱导高胆固醇模型以后,按血浆总胆固醇浓度将动物均衡分为2组,分别喂饲含酪蛋白和大豆活性肽的纯合成高脂饲料56d。结果经28d诱导高胆固醇模型后,高胆固醇模型大鼠的TC浓度是阴性对照组的1.51倍。又经56d喂饲含有处理因素的饲料后,酪蛋白组和大豆活性肽组大鼠体重分别增加了（198.5和119.3）g;血浆总胆固醇浓度水平分别为（6.41±0.57和3.01±0.37）mmol/L;TG水平分别为（3.73±0.70和2.13±0.61）mmol/L;粪胆汁酸含量分别为（0.75±0.13和0.96±0.17）mmol/d;与酪蛋白组相比,大豆活性肽组动物体重及TC,TG和apoB含量显著降低,而粪胆汁酸含量显著增加（P〈0.05）。大豆活性肽组可使大鼠肝脏HMG-CoA还原酶 mRNA,LDL-R mRNA的表达增强。结论膳食大豆活性肽摄入可降低高胆固醇模型大鼠TC、TG、apoB浓度、使粪胆汁酸排泄量增高,但对HDL-C,apoA水平无影响。另外,大豆活性肽可以增强大鼠肝脏HMG-CoA还原酶及LDL-R基因的表达,这可能是其降低血浆胆固醇的机理之一。大豆活性肽可影响血浆胆固醇水平,但其相应的作用机理还需进一步探讨。     

大豆蛋白对大鼠血脂代谢影响

目的探讨大豆蛋白在普通饮食和高脂饮食状态下对大鼠血清脂质水平的影响及作用机制。方法 48只清洁级SD大鼠,按体重随机分为4组,分别喂饲含酪蛋白和大豆蛋白的普通饲料和高脂饲料28 d后,脱颈椎处死动物,检测血脂指标及基因表达水平。结果大豆蛋白组大鼠血清胆固醇(TC)浓度(1.36±0.38)mmol/L,比酪蛋白组(1.97±0.42)mmol/L低31%(P0.05);大豆蛋白高脂组大鼠血清TC、甘油三酯(TG)和低密度脂蛋白胆固醇(LDL-C)浓度分别为(1.43±0.22),(0.53±0.14)和(0.25±0.06)mmol/L,分别比酪蛋白高脂组(2.03±0.31),(0.79±0.20),(0.31±0.06)mmol/L降低30%,33%和19%(P0.05)。大豆蛋白组大鼠肝脏3-羟基-3-甲基戊二酸辅酶A(HMG-CoA)还原酶及低密度脂蛋白受体(LDL-R)基因的表达均高于酪蛋白组。结论大豆蛋白通过影响HMG-CoA还原酶及LDL-R基因的表达调节血脂水平。     

不同来源膳食蛋白质对大鼠体重及其血脂的影响

目的探讨不同膳食蛋白质摄入对大鼠体重及其血脂的长期动态影响。方法选用36只雄性成年Wistar大鼠,按体重随机分为酪蛋白组、大豆蛋白组和谷豆蛋白混合组,喂养12周,检测大鼠在体重及其血脂上的变化。结果大豆蛋白组体重、脂肪湿重、脂体比、TG和TC水平均显著低于酪蛋白组相应指标(P<0.05),HDL-C水平与酪蛋白组相比无统计学差异;谷豆蛋白混合组TC和TG水平均显著低于酪蛋白组和大豆蛋白组(P<0.05),HDL-C水平高于酪蛋白组,有统计学差异(P<0.05)。结论大豆蛋白可以降低大鼠TC和TG水平,谷豆蛋白混合后对TC和TG水平降低作用更明显,并有提高HDL-C的作用。     

大豆蛋白降低大鼠血浆胆固醇机理的初步探讨

目的初步探讨大豆蛋白在大鼠体内降低血胆固醇的可能机理.方法 Wistar雌性大鼠,经14天诱发高血胆固醇模型后,以2×2析因设计,分别喂饲含有20%酪蛋白或大豆分离蛋白和正常钙(0.59%)或高钙浓度(1.12%)的纯合成高脂饲料21天.实验结束前,测血浆总胆固醇浓度,收集3天粪便,测定脂肪、钙、磷、镁的消化率及粪胆汁酸排出量.结果同酪蛋白组相比,其它各组动物的血浆胆固醇浓度及钙和磷的消化率显著下降(P＜0.05).大豆蛋白组动物的脂肪消化率低于其它各组动物,而大豆蛋白高钙组动物的粪胆汁酸排出量高于其它各组动物.结论本实验结果提示大豆蛋白在大鼠体内降血胆固醇机理可能与大豆蛋白本身的非磷酸化状态有关.     

大豆蛋白对大鼠血脂调节的作用机制

目的 探讨大豆蛋白对大鼠血脂代谢的影响及其可能的作用机制.方法 SPF级雄性SD大鼠48只,进食基础饲料适应性喂养2周,随机分为4组:大豆蛋白组,酪蛋白组,大豆蛋白高脂组,酪蛋白高脂组.进食实验饲料28d.测定试验蛋白中氨基酸含量,大鼠血清中血脂、胰岛素和胰高血糖素水平.结果 与酪蛋白相比,大豆蛋白的赖/精比值小,蛋氨酸含量低,胱氨酸含量高.大豆蛋白组大鼠TC、HDL-C浓度及TC/HDL-C比值比酪蛋白组低.大豆蛋白高脂组大鼠血清TC、TG、LDL-C浓度及TC/HDL-C比值比酪蛋白高脂组低.大豆蛋白组大鼠血清胰岛素浓度比酪蛋白组低.大豆蛋白高脂组大鼠血清胰岛素浓度比酪蛋白高脂组低,胰高血糖素浓度比酪蛋白高脂组高.结论 大豆蛋白可通过影响血清中胰岛素/胰高血糖素比率及其氨基酸种类和含量来调节血脂水平,其作用机制还需进一步探讨.     

钙摄入量对大鼠血浆胆固醇水平影响

目的 探讨钙摄入量对大鼠肝脏胆固醇代谢关键酶3-羟基-3-甲基戊二酰辅酶A还原酶(HMG-CoA还原酶)、7α-羟化酶(CYP7A)的mRNA表达影响.方法 雄性Wistar大鼠经14 d诱导高胆固醇血症模型后,分别喂饲不同钙含量的纯合成高脂饲料42 d.结果 经14 d诱导高胆固醇模型后,高脂模型组大鼠血浆胆固醇(TC)水平为(2.57±0.57)mmol/L(n=21),是常脂常钙组(1.49±0.14)mmol/L(n=8)的1.72倍.又经42 d喂饲含有处理因素的饲料后,各组大鼠摄食量和体重无变化;高脂高钙组心脏指数和肾脏指数分别显著低于、高于其他各组(P<0.05);随着钙含量增加,实验处理组大鼠骨密度也逐渐增加;高脂常钙组TC浓度为(2.32±0.75)mmol/L,比初始时下降了6.07%;高脂中钙组抑制TC增高能力强于常脂常钙组;除高脂高钙组外,钙摄入可使大鼠肝脏HMG-CoA还原酶mRNA的表达量呈现下降趋势,CYP7A mRNA的表达量呈现增强趋势.结论 适量钙摄入可通过影响HMD-CoA还原酶和CYP7A基因的表达来降低或改善血浆胆固醇水平.     

不同饲料组成对大鼠血脂的影响

目的比较分析不同种类饲料对大鼠血脂的影响。方法 40只雄性SD大鼠,按体重随机分为4组,每组10只:基础饲料组,5%猪油+1.2%胆固醇组,10%氢化椰子油高糖组和10%牛油高糖组。实验第1周和第6周末检测大鼠血清总胆固醇(total cholesterol, TC)、甘油三酯(triglyceride, TG)、高密度脂蛋白胆固醇(high density lipoprotein-chlesterol, HDL-C)和低密度脂蛋白胆固醇(low density lipoprotein-cholesterol, LDL-C)含量。结果实验第1周,5%猪油+1.2%胆固醇组TC[(2.77±0.47)mmol/L]、LDL-C[(1.53±0.42) mmol/L]显著高于基础饲料组(P<0.05),HDL-C[(1.00±0.14) mmol/L]显著低于基础饲料组(P<0.05),10%氢化椰子油高糖组和10%牛油高糖组TG[(3.58±1.28)和(4.17±1.68)mmol/L]均显著高于基础饲料组(P<0.05)。实验第6周,5%猪油+1.2%胆固醇组和10%氢化椰子油高糖组TC[(2.54±0.60)和(2.73±0.40) mmol/L]均显著高于基础饲料组(P<0.05);10%氢化椰子油高糖组和10%牛油高糖组TG[(2.84±0.79)和(4.16±1.65) mmol/L]均显著高于基础饲料组(P<0.05)。10%氢化椰子油高糖组第6周TC、LDL-C和HDL-C均显著高于第1周(P<0.05),TG显著低于第1周(P<0.05)。结论含有外源性胆固醇的饲料可以使大鼠血清TC和LDL-C显著升高,并降低HDL-C。牛油高糖饲料与氢化椰子油高糖饲料相比,大鼠血清TG水平更高,但能维持TC水平不发生显著改变。提示饲料中添加不同种类的脂肪对大鼠血脂水平的影响也不相同。     

大豆蛋白对大鼠血浆胆固醇影响及作用机制

目的探讨膳食大豆蛋白对高胆固醇模型大鼠血浆胆固醇及其相关血脂指标的影响及可能的作用机制。方法4周龄断乳雄性Wistar大鼠，诱导高胆固醇模型28d后，按体重和血浆总胆固醇浓度均衡分为2组，分别喂饲含酪蛋白和大豆蛋白的纯合成高脂饲料56d。结果酪蛋白组和大豆蛋白组大鼠TC、甘油三酯（TG）、载脂蛋白B（apoB）含量显著降低，粪胆汁酸排泄量增高。但对高密度脂蛋白胆固醇（鼢L—C），载脂蛋白AⅠ（apoA—Ⅰ）zk平无影响；同时可见，大豆蛋白可以增强大鼠肝脏3-羟基-3-甲酰基CoA（HMG—CoA）还原酶及低密度脂蛋白受体（LDL—R）基因的表达。结论大豆蛋白可通过影响apoB、HMG—CoA还原酶及LDL—R基因的表达来改变血浆胆固醇水平，其作用机制还需进一步探讨。     

Increasing intake of soybean protein or casein, but not cod meal, reduces nephrocalcinosis in female rats.

Female weanling rats were fed diets with soybean protein, casein or cod meal at 171, 342 or 513 mmol nitrogen/100 g for 3 wk. The diets were isonitrogenous and balanced for fat, cholesterol, calcium, magnesium and phosphorus. Cod meal feeding at 171 and 342 mmol nitrogen/100 g diet produced lower kidney calcium concentrations than the feeding of either soybean protein or casein. Increasing protein intakes were associated with reduced kidney calcium concentrations in the rats fed either soybean protein or casein but not in those fed cod meal. The anti-nephrocalcinogenic effect of increasing intakes of soybean protein may relate to the lowering of urinary phosphorus concentration. Increasing intakes of casein probably inhibited nephrocalcinogenesis by lowering urinary pH and raising urinary magnesium concentration. Increasing cod meal concentrations in the diet lowered urinary pH and raised urinary magnesium and calcium concentrations, but the effects on nephrocalcinogenesis of these changes probably counteracted each other.     

Hamsters and guinea pigs differ in their plasma lipoprotein cholesterol distribution when fed diets varying in animal protein, soluble fiber, or cholesterol content.

There were two objectives to these studies: 1) to compare the lipoprotein cholesterol distribution in two animal models in response to different dietary treatments and 2) to assess whether the hypercholesterolemia induced by high cholesterol intake could be reversed by consumption of vegetable-protein and/or dietary fiber. Guinea pigs, which carry the majority of plasma cholesterol in LDL, and hamsters, with a higher distribution of cholesterol in HDL, were evaluated in three different studies. In Study 1, animals were fed semi-purified diets for 4 wk with proportions of 60:40, 20:80 or 0:100 (w/w) of casein/ soybean protein. Hamsters and guinea pigs that consumed 100% soybean protein had lower plasma total cholesterol (TC) than those fed diets containing casein (P < 0.01). In Study 2, three doses of dietary pectin (2.7, 5.4, or 10.7 g/100g) added in place of cellulose were tested. Intake of 10.7 g/100 g pectin resulted in the lowest plasma TC concentrations for both species (P < 0.01). Although the TC lowering was similar in studies 1 and 2, the lipoprotein cholesterol distribution differed. Whereas the differences in plasma cholesterol were in LDL in guinea pigs, hamsters exhibited differences in both non-HDL and HDL cholesterol. In study 3, animals were fed 100% soybean protein, 10.7 g/100 g pectin, and three doses of dietary cholesterol: 0.04, 0.08, or 0.16 g/100 g, which is equivalent to 300, 600, or 1,200 mg/d in humans. Guinea pigs and hamsters had the highest plasma LDL and hepatic cholesterol concentrations when they consumed 0.16 g/100 g of cholesterol (P < 0.01). However, intake of 0.08 g/100 g of cholesterol resulted in lower plasma LDL cholesterol concentrations than did consuming high animal protein (60:40 casein/ soy) or low soluble fiber (2.7 g/100 g). Relatively high levels of dietary cholesterol combined with vegetable protein and soluble fiber resulted in desirable lipoprotein profiles in animal models that significantly differ in their lipoprotein cholesterol distribution.     

Inhibitory effect of dietary soybean protein vs. casein on magnesium absorption in rats

The effects of casein and soybean protein on magnesium absorption and magnesium concentration in the femur were investigated in rats. Purified diets containing either casein or soybean protein and three concentrations of added magnesium (0.82, 1.64 or 2.46 mmol/100 g diet) were used. The isonitrogenous diets were carefully balanced for the different mineral concentrations in the protein preparations. Absolute and percent magnesium absorption and urinary magnesium excretion were significantly decreased in rats fed soybean protein when compared with casein, irrespective of the dietary concentration of added magnesium. The magnesium content of femur was significantly lower in rats fed soybean protein, but this effect was seen only when the diet contained 0.82 mmol magnesium/100 g diet. The addition of sodium phytate to the casein diets, to a concentration identical to that in the diets containing soybean protein as provided by the soybean protein preparation, produced similar effects on magnesium absorption as the diets containing soybean protein. These results indicate that soybean protein, when compared with casein, decreases magnesium absorption through its phytate component.     

Lipid metabolism in hypercholesterolemic rats affected by feeding cholesterol-free diets containing different amounts of non-dialyzed soybean protein fraction

OBJECTIVE: We investigated lipid metabolism in hypercholesterolemic rats after replacing casein with different amounts of undialyzed soybean protein fraction. METHODS: The hypercholesterolemic rats were fed cholesterol-free diets containing 2%, 5%, or 10% undialyzed soybean protein fraction (UDSP) for 4 wk. RESULTS: The 5% and 10% UDSP groups had significantly lower plasma cholesterol, triacylglycerol, and low-density lipoprotein cholesterol concentrations than did the other groups (P < 0.05). In addition, significantly higher fecal total steroid excretion was observed in these two groups. However, the different amounts of UDSP did not influence liver lipid, plasma high-density lipoprotein cholesterol, body weight gain, daily food intake, or feeding efficiency. CONCLUSION: These results suggested a dose-dependent reduction in plasma cholesterol when casein was replaced stepwise with UDSP (5% or 10%) as a protein source. The hypocholesterolemic effect might have been due to an increase in total fecal steroid excretion.     

Comparison of the hypocholesterolemic effects of dietary soybean protein with those of formaldehyde-treated casein in rabbits

Treatment of casein with formaldehyde changes its tertiary structure and decreases its hypercholesterolemic properties in rabbits. To investigate whether formaldehyde-treated casein exerts this hypocholesterolemic effect in the same manner as soybean protein, rabbits were fed high or low cholesterol diets containing soybean protein, casein, formaldehyde-treated casein or a mixture of casein and formaldehyde-treated casein. Formaldehyde-treated casein was hypocholesterolemic when fed in a low, but not in a high, cholesterol diet. The hypocholesterolemic effect of soybean protein was independent of the amount of cholesterol included in the diet. In contrast to rabbits fed soybean protein, steroid absorption in those fed formaldehyde-treated casein did not differ from that in rabbits fed native casein. Furthermore, the absorption of phosphorus and nitrogen was lower in rabbits fed formaldehyde-treated casein than in those fed native casein, whereas the absorption found in rabbits fed soybean protein resembled that of their casein-fed counterparts. The diets containing soybean protein and formaldehyde-treated casein produced a comparable ratio of lysine to arginine in serum. The results presented in this paper indicate that the hypocholesterolemic action of dietary formaldehyde-treated casein does not resemble that of soybean protein.     

Interaction of dietary protein differing in sulfur amino acid content and pectin on bile acid conjugation in immature and mature rats

Rapidly growing immature (4-wk-old) and slowly growing mature (15-wk-old) rats were fed fiber-free or 10 g/100 g pectin diets containing various proteins differing in the sulfur amino acid content for 30-32 d. Soybean protein, casein, whole egg protein and egg albumen were used at the nitrogen level of 2.7 g/100 g diet. These experimental diets contained 0.354, 0.540, 0.945 and 1.22 g sulfur amino acids/100 g, respectively. In the rats fed fiber-free diets, a substantial quantity of glycine-conjugated bile acids was detected in the bile of immature rats fed soybean protein and casein (73 and 25% of total bile acids, respectively), but not in the other groups (less than 13%). Dietary pectin increased bile acid excretion both in immature (48-77%) and mature (34-114%) rats irrespective of the protein source, except in immature rats fed egg albumen and mature rats fed whole egg protein. Because a pectin-dependent increase in bile acid excretion was essentially attributed to the increase in glycine-conjugates, this dietary fiber significantly increased the ratio of glycine-conjugates to taurine-conjugates (2.4- to 6.5-fold). This increase was accompanied by a 40-50% decrease in the concentration of liver taurine, except in immature rats fed soybean protein and egg albumen. However, there was no consistent relationship between the extent of taurine conjugation and the activity of liver cysteine dioxygenase, one of the rate-limiting enzymes in taurine synthesis.     

Effects of feeding oyster,Crassostrea gigas,on serum and liver lipid levels in rats

The effects of feeding dietary and defatted oyster meat on lipid metabolism were investigated in rats by comparing measurements with those of casein and soybean protein. In the first experiment, male rats were fed 0.1% and 1% cholesterol-supplemented diets containing casein, oyster or soybean protein under the same dietary level of protein (20%). The concentrations of serum and liver cholesterol in the oyster group were significantly lower than those in the casein group for both the 0.1% and 1% cholesterol-supplemented diets. The cholesterol-lowering effect of oyster meat was more predominant than that of soybean protein. Feeding oyster meat significantly decreased the serum triglyceride concentration as compared to feeding casein for the 0.1% cholesterol-supplemented diets, and it reduced hepatic triglyceride concentration in both groups fed the 0.1% and 1% cholesterol-supplemented diets. The excretion of fecal total steroids was higher in the rats fed oyster meat than those fed casein or soybean protein for both the 0.1% and 1% cholesterol-supplemented diets. In the second experiment, the effects of defatted oyster on lipid metabolism were compared with casein and soybean protein in diets supplemented with cholesterol. The serum cholesterol concentration in the defatted oyster group was comparable to that in the other two groups, but the ratio of high-density lipoprotein-cholesterol to total cholesterol was higher in the defatted oyster group. The feeding of defatted oyster induced a lower liver cholesterol concentration as compared to casein and soybean protein. Serum and liver triglyceride levels were lower in the defatted oyster group than in the casein group. Defatted oyster accelerated the fecal excretion of both neutral and acidic steroids as compared to casein. Our results suggest that the feeding of oysters exerts a more potent hypolipidemic activity than soybean protein, and the effect may be ascribed to both lipid and non-lipid fractions in oyster.