合成油的营养评价——(二)合成油饲料对实验性高胆固醇血症大鼠体重、血脂和肝脂成分的影响

在88g基础饲料中加入12g不同种类的油脂(合成油、猪油和豆油)和1％胆固醇喂养大鼠5周以诱导动物产生高脂血症,并以不加入胆固醇的豆油饲料作为正常对照。比较各组动物在实验期内的生长、血清脂质、肝脏脂质和某些内脏器官重量的改变。结果如下: (1)大鼠摄食含不同油脂的致高胆固醇血症饲料5周后,各组雄鼠的体重增加无明显的不同,雌鼠的体重增加则有显著的差别,即合成油组动物的增重显著较猪油组和对照组的为低。 (2)在各种油脂饲料中加入胆固醇都可使动物的肝重增大。猪油组和豆油组动物的肝脏有明显的脂肪肝病变。肝脂含量增加,肝胆固醇和甘油三酯大量积存(分别约为对照组的9-10倍和2-3倍)。而合成油组动物的肝脏外观表现正常,肝脂含量、肝胆固醇和甘油三酯水平则接近对照组的正常水平。 (3)在各种油脂饲料中加入胆固醇喂养大鼠,对雄鼠血清胆固醇水平的影响不明显,但引起雌鼠血清胆固醇的改变和对照组比较,猪油饲料使动物的血清胆固醇含量明显增高,豆 油和合成油饲料则可维持动物的血胆固醇含量于正常水平。血清甘油三酯水平则以合成油饲料组动物的为最高。 (4)在各种饲料中加入胆固醇除增大肝脏重量外,也使雌鼠的主动脉重量增高,但饲料油脂种类对其重量的影响不明显。 上述结果表明,当饲料中含有高水?     

Lipid profile of rats fed high-fat diets based on flaxseed, peanut, trout, or chicken skin

OBJECTIVE: Dietary saturated fatty acids are associated with coronary disease. Conversely, dietary monounsaturated polyunsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) seem to exert a protective effect. This study evaluated the lipid profile of rats fed high-fat (HF) diets, with fat added as different sources of PUFA (flaxseed and trout), MUFA (peanut), and saturated fatty acid (chicken skin). METHODS: Adult male Wistar rats were placed into six dietary groups (n = 10): control (normal); high fat, with 1% cholesterol, 10% soy oil, and 5% lard; and four groups fed similar HF diets, with 10% lipid as trout, flaxseed, peanut, or chicken skin. After 28 d the animals were killed. Blood, livers, and adipose tissue samples were collected. RESULTS: A higher level (P < 0.05) of total serum cholesterol was observed in rats fed the normal diet (93.57 +/- 14.95 mg/dL) compared with those fed the HF diet (67.57 +/- 12.54 mg/dL). Total cholesterol levels in rats fed the flaxseed diet were lower (P < 0.05) than in rats fed the other fats. No difference was observed in cholesterol levels between groups fed the peanut and chicken skin diets (P > 0.05). Animals fed the peanut diet showed decreased body weight gain than did animals in the other treatment groups. There were large lipid and cholesterol depositions in livers of rats fed the HF diet. Lipid deposition in adipose tissue followed the same dietary fatty acid profile, i.e., high levels of omega-3 PUFA in the flaxseed group, high levels of MUFA in the peanut and chicken skin groups and high levels of omega-6 PUFA in the trout group. CONCLUSIONS: These data indicate that flaxseed is promising for dietary manipulation of hyperlipidemia.     

A High-Fat Diet Differentially Affects the Gut Metabolism and Blood Lipids of Rats Depending on the Type of Dietary Fat and Carbohydrate

The aim of this model study was to investigate how selected gut functions and serum lipid profile in rats on high-fat diets differed according to the type of fat (saturated vs. unsaturated) and carbohydrate (simple vs. complex). The experiment was conducted using 32 male Wistar rats distributed into 4 groups of 8 animals each. For 4 weeks, the animals were fed group-specific diets that were either rich in lard or soybean oil (16% of the diet) as the source of saturated or unsaturated fatty acids, respectively; further, each lard- and soybean oil-rich diet contained either fructose or corn starch (45.3% of the diet) as the source of simple or complex carbohydrates, respectively. Both dietary factors contributed to changes in the caecal short-chain fatty acid concentrations, especially to the butyrate concentration, which was higher in rats fed lard- and corn starch-rich diets compared to soybean oil- and fructose-rich diets, respectively. The lowest butyrate concentration was observed in rats fed the soybean oil- and fructose-rich diet. On the other hand, the lard- and fructose-rich diet vs. the other dietary combinations significantly increased serum total cholesterol concentration, to more than two times serum triglyceride concentration and to more than five times the atherogenic index. In conclusion, a high-fat diet rich in fructose can unfavorably affect gut metabolism when unsaturated fats are predominant in the diet or the blood lipids when a diet is rich in saturated fats.     

合成油的营养评价——(三)在实验性高脂血症大鼠的恢复期中合成油对其体重、肝重、血脂与肝脂水平的影响

在12％猪油饲料中加入胆固醇和胆酸饲养雌性断乳大鼠52日,以诱导动物产生高胆固醇血症。然后根据血清胆固醇水平和体重将大鼠分为4组,其中1组被处死作为负对照,另3组则分别饲以无胆固醇和胆酸的合成油,猪油或豆油饲料3周,观察不同油脂饲料对大鼠恢复的影响。在实验期内,测量体重、记录摄食量、测定粪的类固醇排出量、测定血清胆固醇总量和HDL含量、称量肝重和测定肝胆固醇含量。实验结果如下: (1)在恢复期的3周内,合成油组的动物体重增加和摄食量均显著低于其他两组。用共变数分析方法消除其摄食量的影响后,各组动物的体重增加尤显著性差别。 (2)52日诱导期末,大鼠血清总胆固醇量平均增为450mg/dl。恢复期的第一周即下降了60％,但到第3周时仍未能恢复到正常水平。3个组在任何一周的均值都未现出明显不同。 (3)HDL-C的测定结果指出在3周的恢复期后,猪油组的明显低于其他两组。 (4)动物的肝重和肝脂含量的恢复情况相似。肝胆固醇水平则以猪油组的较高,合成油和豆油组的均值间无显著性差别。 (5)粪的固醇平衡实验结果表明,在恢复期,猪油饲料组动物的粪中性类固醇排出量最低,固醇平衡量最高。 总结上述结果,可以看到在大鼠高胆固醇血症的恢复过程中,饲料油的种类对动物的体重、血清胆固醇、肝重和肝脂含量无     

猪油与豆油对大鼠主动脉影响的扫描电镜观察

本实验观察了猪油与豆油对大鼠血脂水平和主动脉形态学改变的影响。成年雄性Ｗｉｓｔａｒ大鼠２４只分为猪油组、豆油组和对照组。观察结果表明：饲以高脂膳食２０天后，高脂组大鼠血清胆固醇水平显著高于对照组，猪油组显著高于豆油组。此后４０天，各组动物血清胆固醇含量维持在相对稳定的水平。至６０天时，在扫描电镜下可见高脂组大鼠主动脉发生病变，主要内皮细胞肿胀变形，排列紊乱，偶可见微血栓形成。猪组病变重于豆油组。     

富含EPA浓缩鱼油抑制血小板聚集的机理探讨

流行病学和实验室资料均提示富含EPA鱼油(简称鱼油)具有抑制血小板聚集和抗血栓形成的作用。本文主要探讨鱼油抑制血小板聚集的机理。实验分别将大鼠和家兔随机分成4组:正常组、高脂组、鱼油组、橄榄油组。按各自不同饲料喂养3个月以后,4组大鼠血浆TXB_2/6-酮-PGF_(1a)比值分别为1.4,2.2,1.0,1.7。鱼油组血小板内cAMP含量明显高于高脂组(P<0.05)。鱼油组血清总胆固醇值、血浆TXB_2、5-羟色胺(5-HT)、钙离子浓度、纤维蛋白原含量及血液粘度(低切)均明显低于高脂组(P<0.05)。鱼油组血浆、血小板、心肌及肝脏中EPA、DHA含量明显高于其它3组(P<0.001)。以上结果提示,鱼油抑制血小板聚集和血栓形成的机理可能是,鱼油中的EPA和DHA等高不饱和脂肪酸纳入细胞膜后竞争抑制花生四烯酸(AA)代谢,减少血小板TXA_2生成和释放,降低血中TXA_2/PGI_2比值,同时增加血小板内cAMP含量,稳定血小板功能,减少5-HT,钙离子等具有促聚活性物质释放。另外,鱼油降低血脂、血浆纤维蛋白原含量及血液粘度,从而改善血液流变性,使血小板本身及其周围环境得以改善,防止血小板聚集和血栓形成。     

Anti-obesity and hypolipidemic effects of black soybean anthocyanins

The effect of anthocyanins extracted from black soybean (Glycine max L.) seed coats on body weight, adipose tissue weight, and serum lipids was evaluated in rats fed a high fat diet (HFD). Rats were raised on a normal diet (ND) (based on the AIN-93M diet), HFD (ND supplemented with 16% lard oil), HFD containing 10% black soybean, and HFD containing 0.037% black soybean anthocyanins (equivalent to that in the 10% black soybean diet). Weight gain was significantly lowered in the rats fed HFD plus black soybean anthocyanins compared with the rats fed HFD alone (P < .05) and reversed to the level of the rats fed ND. The black soybean diet also decreased body weight gain compared with the HFD (P < .05). The black soybean anthocyanins-added diet suppressed the HFD-induced weight gain in liver intermediately and tended to decrease the weights of epididymal and perirenal fat pads. The black soybean anthocyanins were also effective in improving the lipid profile. They significantly reduced the levels of serum triglyceride and cholesterol (P < .05), while they markedly increased the high-density lipoprotein-cholesterol concentration, which was decreased in the rats fed HFD (P < .05). These results indicate that the anthocyanins in black soybean seed coats have an anti-obesity effect, which can reverse the effects of HFD on body weight, adipose tissue weight, and serum lipid contents.     

The influence of dietary isomeric and saturated fatty acids on atherosclerosis and eicosanoid synthesis in swine

Weanling swine were fed for 6 months high fat diets containing as fat source, a high oleic acid safflower oil, lard, or a partially hydrogenated soybean oil blended with soybean oil. The extent of atherosclerosis in left coronary arteries and the ability of vascular components to synthesize eicosanoids important for blood clotting were determined. There was no significant difference (p greater than 0.05) in the extent of atherosclerosis or the synthesis of thromboxane A2. Significant effects were observed on serum cholesterol, which was elevated in the lard fed group, serum triacylglycerol, which was highest in the safflower oil group, and prostacyclin synthesis, which was depressed in both the lard and hydrogenated soybean oil diets compared to the safflower oil diet. No unique effect on the development of heart disease appears to be attributable to hydrogenated fats. The hydrogenated fat was similar to lard in decreasing prostacyclin synthesis, suggesting that the saturation of dietary fatty acids may be a contributory factor in the development of heart disease, through its effect on thrombotic processes.     

Effects of diets rich in fermentable carbohydrates on plasma lipoprotein levels and on lipoprotein catabolism in rats

This study was conducted to examine the effects of a combination of several dietary fibers (5% guar gum, 5% apple pectin, 15% wheat bran, 22% soybean fiber) and crude potato starch (23%) on plasma lipids and lipoproteins and on liver lipid concentration in rats fed a diet containing either 15% lard or 5% oil with or without dietary cholesterol/cholic acid. Male Wistar rats ate the test diets for 3 wk. The incorporation of fiber and crude potato starch into the diet resulted in a significant enlargement of the cecum; it also increased the concentration of volatile fatty acids and the pool of acetate, propionate and butyrate. Feeding this fermentable carbohydrate decreased plasma cholesterol and triglyceride levels in rats given a low fat diet and prevented the expected rise in plasma cholesterol and triglycerides in rats fed cholesterol/cholic acid or lard. Further studies of high density lipoprotein (HDL) composition, 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMG-CoA reductase) activity and 125I-labeled human low density lipoprotein (LDL) turnover were done in the group fed the low fat diet without added cholesterol/cholic acid. The study of the HDL fraction in rats fed a diet rich in fermentable carbohydrates demonstrated a decrease in the HDL1 subpopulation and in the proportion of apolipoprotein E. Plasma clearance of intravenously injected 125I-labeled LDL was faster in rats fed this diet than in rats fed the fiber-free diet. In the liver, cholesterol and triglyceride levels were depressed whereas the activity of HMG-CoA reductase was increased.(ABSTRACT TRUNCATED AT 250 WORDS)     

MYLIP p.N342S polymorphism is not associated with lipid profile in the Brazilian population

Background

Atherosclerosis is a major manifestation of the pathophysiology underlying cardiovascular disease. Flaxseed oil (FO) and ??-lipoic acid (LA) have been reported to exert potential benefit to cardiovascular system. This study tried to assess the effect of supplement of FO and LA combination on the atherosclerosis risk factors in rats fed a high-fat diet.

Methods

LA was dissolved in flaxseed oil to a final concentration of 8 g/kg (FO+LA) when used. The rodent diet contained 20% fat. One-fifth of the fat was soybean oil and the others were lard (HFD group), or 75% lard and 25% FO+LA (L-FO+LA group), or 50% lard and 50% FO+LA (M-FO+LA group), or FO+LA (H-FO+LA group). Animals were fed for 10 weeks and then killed for blood collection.

Results

Supplement of FO and LA combination significantly enhanced plasma antioxidant defense capacities, as evaluated by the marked increase in the activities of SOD, CAT and GPx as well as the level of GSH, and the significant reduction in lipid peroxidation. Simultaneous intake of FO and LA also reduced plasma TG, TC and LDL-C contents and elevated the ratio of HDL-C/LDL-C. Besides, in parallel with the increase of FO and LA combination, plasma IL-6 and CRP levels were remarkably reduced.

Conclusion

Supplement of FO and LA combination may contribute to prevent atherogenesis by improving plasma oxidative stress, lipid profile and inflammation.     

Menhaden oil inhibited gamma-glutamyltransferase-positive altered hepatic foci in female Sprague-Dawley rats

Feeding menhaden oil, high in n-3 fatty acids, or a mixture of lard and corn oil with a polyunsaturated-to-monounsaturated fatty acid ratio of 1:1 was hypothesized to inhibit promotion of hepatocarcinogenesis in rats by decreasing hepatic prostaglandin (PG) levels. Ten-day-old female Sprague-Dawley rats were injected with diethylnitrosamine (DEN, 15 mg/kg body wt ip). At 4 wk of age, rats were fed fumonisin B1(50 mg/kg diet) for 5 wk in diets containing 14% lard + 6% corn oil, 10% lard + 10% corn oil, 14% menhaden oil + 6% corn oil, and 7% menhaden oil + 13% corn oil. Plasma alanine aminotransferase activity was 20% lower in rats fed 10% lard than in rats fed the other diets (P < 0.05). In menhaden oil-fed rats, total plasma cholesterol concentrations decreased 26% (P < 0.05) and hepatic phospholipid C20:5n-3, C22:5n-3, and C22:6n-3 fatty acid concentrations increased compared with lard-fed rats. Hepatic n-3 fatty acids were threefold greater in rats fed 10% lard than in rats fed 14% lard. The liver-associated natural killer cell activity in rats fed menhaden oil was 58% lower than in rats fed lard (P < 0.03). Rats fed lard had threefold (P < 0.05) greater area of _-glutamyltransferase-positive altered hepatic foci (AHF) than did rats fed menhaden oil. There was no significant difference in placental glutathione S-transferase-positive AHF among the groups. Hepatic PGF2alpha production was 60-80% greater in rats fed 14% lard than in rats fed the other diets (P < 0.05). Hepatic PGE2 was 48% less in rats fed 14%; menhaden oil than in rats fed 14% lard (P < 0.05). Although gamma-glutamyltransferase-positive focal area was inhibited by menhaden oil, only 14% menhaden oil inhibited PGE2. Feeding 10% lard inhibited PGF2alpha, but not the development of AHF. Therefore, decreased hepatic PGs did not explain the inhibition of carcinogenesis.     

玉米油和猪油对大鼠血脂血糖代谢和脑脂褐质影响的比较研究

采用幼年ＳＤ雄性大鼠３０只，体重１５０±２０ｇ，随机分成三组，每组１０只：（１）基础饲料组：普通大鼠饲料；（２）猪油组：基础饲料中加入１０％猪油和１．５％胆固醇；（３）玉米油组：在基础饲料中加入１０％玉米油和１．５％胆固醇，饲养９周，比较玉米油和猪油对大鼠血脂血糖和脑脂褐质的不同影响。结果表明，玉米油组ＴＣ和ＬＤＬ－Ｃ水平较猪油组低，虽然两组均高于基础饲料组。玉米油组的ＨＤＬ－Ｃ比猪油升高不显著，但ＨＤＬ－Ｃ／ＴＣ（％）增加，同时ＬＤＬ－Ｃ／ＨＤＬ－Ｃ比值下降。基础饲料组，猪油组和玉米油组的大鼠平均血清ＴＧ分别为１.２８，１.２１和１.４５（ｍｍｏｌ／Ｌ），各组之间的差别不显著。高脂饲料组动物的空腹血糖（ＳＧ）较基础饲料组高，但差别无统计学意义。三组不同饲料大鼠的脑脂褐质（ＬＰＦ）含量测定结果显示:基础饲料组大鼠的ＬＰＦ平均值１２.９Ｕ／ｇ蛋白质，而玉米油组和猪油组均明显升高，分别为２８.３和２８.８Ｕ／ｇ蛋白质。在以血脂各项指标为自常量，大脑ＬＰＦ含量为因变量的相关分析中发现，ＬＰＦ与ＴＣ和ＬＤＬ－Ｃ呈正相关，相关系数分别为０.６９１和０.５４７，Ｐ＜０.０１．     

大鼠补硒后血谷胱甘肽过氧化酶，维生素E和脑脂褐质的变化

采用猪油（Ｌ）或玉米油（Ｍ）加胆固醇饲料诱导大鼠高脂血症模型以含硒量约为３．５ｍｇ／ｋｇ的富硒饲料Ｌａｒｄ－Ｓｅ（Ｌ一Ｓｅ），Ｍａｉｚｅｏｉｌ－Ｓｅ作为干预因素，观察实验性高脂血症大鼠补硒后血液ＧＳＨ－Ｐｘ，ＶＥ和大脑脂褐质（ＬＰＦ）的变化。结果表明，Ｌ－Ｓｅ组的ＧＳＨ－Ｐｘ活性比Ｌ组升高４２．８６％；玉米油是否加硒的两组（Ｍ和Ｍ－Ｓｅ）动物血清ＶＥ浓度均高于Ｌ，Ｍ－Ｓｅ组比Ｍ组升高２４．７７％。但富硒的Ｌ－Ｓｅ组ＶＥ水平比Ｌ组升高近７３％。此外，补硒动物（Ｌ－Ｓｅ和Ｍ－Ｓｅ）的大脑ＬＰＦ明显低于非补硒组。相关分析的结果显示，血Ｓｅ，肝Ｓｅ含量与ＧＳＨ－Ｐｘ呈明显正相关，血硒与血清ＶＥ呈正相关，肝硒与大脑ＬＰＦ呈明显负相关。上述结果提示，富硒饲料对增强高血脂大鼠体内抗氧化能力，减少脂质过氧化作用有效。     

Serum and liver lipids in rats and chicks fed with diets containing different oils

OBJECTIVES: Because dietary fat composition is determinant for serum cholesterol level, which is related to cardiovascular disease, we evaluated the effects of diets containing saturated (coconut oil) or polyunsaturated fatty acids (soybean oil) supplemented or not with dietary cholesterol on serum and liver lipid composition in two animal species. METHODS: Male Wistar rats (21 d old) were assigned to one of seven groups and fed with commercial diet or diets containing 5% or 20% soybean oil or 20% coconut oil with or without 1% cholesterol. Chicks were assigned to one of four groups and fed with diets containing 15% soybean oil or 15% coconut oil with or without 1% cholesterol. RESULTS: In rats, the accumulations of hepatic cholesterol and triacylglycerols were higher in the group fed 20% soybean oil and 1% cholesterol than in the group fed 20% coconut fat and 1% cholesterol. The highest serum levels of cholesterol and triacylglycerols were observed in the group fed coconut oil and cholesterol, compared with the group fed soybean oil and cholesterol. Triacylglycerol, high-density lipoprotein, and total cholesterol serum levels increased with diet containing coconut oil and cholesterol. In chicks, the highest hepatic cholesterol accumulation occurred in the group fed 15% coconut fat and 1% cholesterol. Total and high-density lipoprotein cholesterol levels increased with diet containing coconut oil and cholesterol, although none of these diets modified serum triacylglycerol levels. CONCLUSIONS: The type of experimental animal model and the diet composition influence lipid metabolism.     

Health benefits of dietary fat reduction by a novel fat replacer: Mimix

The primary goals of this study were to identify any health benefits of the replacement of dietary fat with a novel fat replacer, Mimix, and to assure that the consumption of this fat replacer did not convey any deleterious health effects. Male, weanling, Fischer 344 rats were fed one of six diets containing between 5 and 20% w/w as fat for 8 weeks. These diets included two high fat diets (safflower oil or lard), a low fat diet and three diets where 15% of the fat in the high fat diets was replaced with various amounts of Mimix. When animals were fed a diet rich in saturated fat they consumed significantly more energy than other diet groups. When 15% saturated fat (lard) was replaced with safflower oil animals adjusted their food intake so that no difference in energy intake was observed between the high safflower diet and the low fat and Mimix diets. When the various Mimix fat replacements were compared to animals fed a high fat lard diet there was incomplete compensation of energy intake. Animals fed the high fat lard diet also had higher glucose and total serum cholesterol than their low fat and fat replacement counterparts. Feeding a high fat safflower oil diet to rats resulted in a significantly lower total serum cholesterol and serum triglyceride than all other diets. Replacement of dietary fat with Mimix demonstrated no deleterious effects on the heart, liver and intestinal tract that were all of normal weight, morphology and colour compared to other diet groups. Body composition analysis demonstrated that animals fed high fat diets had higher body fat mass at the expense of lean body mass. This was most obvious for animals fed high fat lard diets who had heavier epididymal fat pads. These data demonstrate that the replacement of dietary fat with the novel fat replacer Mimix can convey a number of health benefits in the absence of any deleterious effects.     

Health benefits of dietary fat reduction by a novel fat replacer: Mimix

The primary goals of this study were to identify any health benefits of the replacement of dietary fat with a novel fat replacer, Mimix, and to assure that the consumption of this fat replacer did not convey any deleterious health effects. Male, weanling, Fischer 344 rats were fed one of six diets containing between 5 and 20% w/w as fat for 8 weeks. These diets included two high fat diets (safflower oil or lard), a low fat diet and three diets where 15% of the fat in the high fat diets was replaced with various amounts of Mimix. When animals were fed a diet rich in saturated fat they consumed significantly more energy than other diet groups. When 15% saturated fat (lard) was replaced with safflower oil animals adjusted their food intake so that no difference in energy intake was observed between the high safflower diet and the low fat and Mimix diets. When the various Mimix fat replacements were compared to animals fed a high fat lard diet there was incomplete compensation of energy intake. Animals fed the high fat lard diet also had higher glucose and total serum cholesterol than their low fat and fat replacement counterparts. Feeding a high fat safflower oil diet to rats resulted in a significantly lower total serum cholesterol and serum triglyceride than all other diets. Replacement of dietary fat with Mimix demonstrated no deleterious effects on the heart, liver and intestinal tract that were all of normal weight, morphology and colour compared to other diet groups. Body composition analysis demonstrated that animals fed high fat diets had higher body fat mass at the expense of lean body mass. This was most obvious for animals fed high fat lard diets who had heavier epididymal fat pads. These data demonstrate that the replacement of dietary fat with the novel fat replacer Mimix can convey a number of health benefits in the absence of any deleterious effects.     

Dietary casein and soybean protein affect the concentrations of serum cholesterol, triglyceride and free amino acids in rats.

This work was undertaken to investigate the concentrations of free amino acids in blood after food was withheld from growing, male Wistar rats fed cholesterol-free, low fat (1 g corn oil/100 g) diets with casein or soybean protein for 2 wk. A diet containing 22.5 or 23.5 g/100 g of soybean protein was hypocholesterolemic compared with a diet containing 20.0 g casein/100 g diet. A comparison of serum amino acids in soybean protein-fed vs. casein-fed rats showed that, whereas concentrations of many amino acids were lower in the soybean protein-fed rats compared with the casein-fed groups, glycine was the only amino acid having a higher concentration. Further, alanine was significantly lower in the soybean protein-fed rats compared with the casein-fed rats, and the protein-induced differences in glycine and alanine concentrations of unfed rats were reproducible. When diets containing 15.0% casein or 30.0% soybean protein, a casein diet supplemented with glycine and a soybean protein diet supplemented with methionine were compared, the changes in serum glycine and alanine correlated with the changes in serum cholesterol. Concentrations of several amino acids, particularly valine, leucine and tyrosine, also changed when serum cholesterol concentrations varied, but these effects could not be explained by our experiments. The results suggest that a change in serum concentration of glycine and alanine of unfed rats may be related to the change in serum cholesterol concentration.     

不同膳食脂肪对糖耐量及胰岛素敏感性的影响

目的:比较4种膳食脂肪对大鼠糖耐量及胰岛素敏感性的影响。方法:将50只SD大鼠随机分为5组,分别为紫苏油组、葵花籽油组、橄榄油组、猪油组和基础饲料组。各膳食脂肪组大鼠的脂肪摄入量占总能量的30.4%。喂养6 w后,进行口服葡萄糖耐量试验(OGTT),测定血清胰岛素、甘油三酯、总胆固醇等指标,并计算胰岛素敏感指数(ISI)。同时分离附睾脂肪垫并称重。结果:与基础饲料组相比,猪油组大鼠葡萄糖餐后2 h血糖及胰岛素显著升高,ISI显著降低;葵花籽油组和橄榄油组大鼠的餐后2 h血糖显著低于猪油组,ISI显著高于猪油组;紫苏油组大鼠空腹及餐后2h血糖、胰岛素水平均显著低于猪油组,ISI高于猪油组,其中空腹血糖还低于葵花籽油组、橄榄油组和基础饲料组,ISI高于上述组。紫苏油组血清甘油三酯、总胆固醇水平显著低于猪油组和基础饲料组,大鼠附睾脂肪垫相对重量显著低于猪油组。结论:猪油可促使胰岛素抵抗及高血糖的发生,而紫苏油可提高大鼠胰岛素敏感性、改善糖代谢;葵花籽油和橄榄油对胰岛素敏感性和糖耐量的作用介于紫苏油和猪油之间。紫苏油对糖代谢的有利作用可能与其降低血中甘油三酯水平、减少体内脂肪堆积有关。     

Modification of plasma and hepatic lipids of guinea pigs by feeding high oleic acid pork compared with regular pork.

Meat from such monogastric animals as swine can be modified to substitute monounsaturated fatty acids for saturated fatty acids. Because monounsaturated fatty acids have a beneficial effect on serum lipids as compared with saturated fatty acids, the objective of this study was to assess the effect of modified pork as compared with regular pork on serum and hepatic lipids. Guinea pigs were fed diets containing pork from control diet-fed hogs or from hogs fed a diet containing high oleic acid sunflower oil. The pork provided almost all of the fat in the diets at the level of 4 and 15 g/100 g diet, 10 or 34% energy. The high oleic pork muscle and fat contained 26 and 46% less palmitic and stearic acids (the primary saturated fatty acids), respectively, and 31 and 29% more oleic acid (the primary monounsaturated fatty acid) than the regular pork muscle and fat, respectively. Cholesterol concentration of diets ranged from 0.06 to 0.08% of the diet. Although total serum cholesterol, HDL cholesterol and triglyceride concentrations did not differ due to type of pork, results indicated that serum LDL cholesterol was lower (15%) and hepatic cholesterol was greater (15%) in the high oleic pork, 15% fat group as compared with the control pork 15% fat group. Also, serum LDL cholesterol concentration was higher in the groups fed 15% fat compared with those fed 4% fat. In this study pork modified to have more oleic acid and less saturated fatty acids had a positive effect on tissue lipids when fed to animals.     

摄入高硒饲料对大鼠肝脏的影响

为研究硒对大鼠脂肪代谢和肝脏的影响，采用雄性SD大鼠40只，随机分成两组，分别饲喂猪油或五米油饲料（LM）。10周后再各自分成两组，其中一级加入亚硒酸钠（L-Se，M-Se）。饲喂10周后处死，测血清谷丙转氨酶含量和肝硒含量，并观察肝脏的病理改变。结果显示：L组和M组大鼠的肝细胞损害严重，呈明显的脂肪肝病变；而加硒的L-Se纽和M-Se组的肝硒含量明显高于未加硒组，肝脏的病变显著减轻，仅有少数肝细胞受到脂肪浸润。结果表明，微量元素硒对高服饲料所致的大鼠脂肪肝有防治作用，其机制有待于进一步研究。