Effect of Mineral Fortification on Plasma Biochemical Profile in Rats

This study aimed at investigating the changes in biochemical profile of male rats following 8 weeks administration of different concentration of elemental iron, sodium iron ethylenediaminetetraacetate (NaFeEDTA), zinc sulfate (ZnSO₄), and zinc oxide (ZnO) in whole wheat flour. Eight groups comprising five rats each were fed fortified whole wheat flour in the form of baked pallets, while one group served as control. Concentration of total cholesterol, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), triglycerides, total proteins, albumin, globulin, plasma glucose, and blood urea nitrogen were assayed. Supplementing mineral-fortified diet to male rats did not indicate any significant (p ≤ 0.05) effect on total cholesterol concentration. Diets containing NaFeEDTA alone increased HDL-C and decreased LDL-C; however, the differences remained non significant. Likewise, plasma triglycerides content of male rats remained unchanged on feeding fortified diets. Diets containing iron as NaFeEDTA and elemental iron exerted little effect on total protein concentration in the plasma of rats. Plasma glucose and blood urea nitrogen levels did not exhibit any significant change as a result of ingesting mineral supplemented diets. The study concludes that the forms of fortificants and the fortification levels used in the current study are undamaging for lipid profile, renal function, and glucose levels in rats, suggesting that these may be safely used in wheat flour to combat iron and zinc deficiency in vulnerable groups.     

Production of platelet thromboxane A2 and arterial prostacyclin I2 from hypercholesterolemic rats.

The plasma cholesterol, plasma malonaldehyde (MDA), platelet thromboxane A2 (TXA2) and vascular prostacyclin (PGI2) were measured in male Sprague-Dawley rats fed diets supplemented with cholesterol (1%) and cholic acid (0.5%). For comparisons, measurements were made in rats fed normal diets. The concentration of cholesterol in the plasma of rats had reached a maximum in 1 week of feeding experimental diets. TXA2 production from collagen and thrombin stimulated platelets was significantly decreased in animals fed experimental diets for 1 week. The production of MDA in the plasma of animals fed experimental diets for 8 weeks was significantly lower compared to the animals fed normal diets. There was a small but significant reduction in the formation of PGI2 in rats fed experimental diets for 8 weeks. These data suggest that feeding cholesterol rich diets to rats alters the platelet membrane properties differently from human and rabbit. Furthermore, cholesterol feeding to rats had some damaging effect on the arterial PGI2 synthesis.     

Hypolipidemic effect of Smallanthus sonchifolius (yacon) roots on diabetic rats: biochemical approach

Fructooligosaccharides (FOS) are sugars found naturally at high concentrations in the storage roots of yacon. This study was designed to analyze the beneficial effects of subchronic oral consumption of yacon root flour as a diet supplement in Streptozotocin-induced diabetic Wistar rats. The experiments were carried out using yacon flour tablets containing the desired level of FOS (340 or 6800 mg FOS/kg body weight/day). Yacon flour is a natural product obtained by a simple process of dehydration of yacon roots without added preservatives or chemicals. The administration of FOS-rich yacon flour to diabetic rats for 90 days did not significantly alter the body weight of animals throughout the experimental period. Interestingly, a significant decrease in fasting plasma triacylglycerol and very low-density lipoprotein levels were observed. In addition, the treatment was able to protect the diabetic rats of the postprandial peak of plasma triacylglycerol. Yacon-supplemented rats showed an increased insulin-positive pancreatic cell mass distributed in small cell clusters within the exocrine parenchyma, but can only observe a slight increase in fasting plasma insulin levels. Glucagon like peptide-1 content in the cecum was significantly higher in diabetic rats treated with a diet supplemented with yacon flour compared with untreated diabetic animals, accompanied by an important cecal tissue enlargement. All these findings lead us to suggest that this incretin could be an effective mediator of the lipid lowering effects of FOS present in yacon flour. In conclusion, yacon root flour is a natural product rich in FOS that could be well positioned as a nutraceutical product since the present results demonstrate its beneficial effects on diabetes-associated hyperlipidemia.     

Effect of gamma-aminobutyric acid-enriched tempeh-like fermented soybean (GABA-Tempeh) on the blood pressure of spontaneously hypertensive rats

GABA-enriched tempeh-like fermented soybean (GABA-tempeh) was supplemented to the AIN-76 diet and fed for 2 months to spontaneously hypertensive rats (SHRs), an animal model of spontaneously developed hypertension, to compare the antihypertensive activity with that of authentic GABA. The elevation of systolic blood pressure in SHRs was significantly retarded in the GABA-tempeh group as well as that with authentic GABA when compared with the controls, and the effect lasted for two months of the feeding period. The blood urea nitrogen level tended to be higher in the control group than in the GABA-supplemented groups. On the other hand, no effect was apparent on the plasma levels of cholesterol, triacylglycerol and glucose, or on the urinary excretion of Na and K.     

Effect of γ-Aminobutyric Acid-enriched Tempeh-like Fermented Soybean (GABA-Tempeh) on the Blood Pressure of Spontaneously Hypertensive Rats

GABA-enriched tempeh-like fermented soybean (GABA-tempeh) was supplemented to the AIN-76 diet and fed for 2 months to spontaneously hypertensive rats (SHRs), an animal model of spontaneously developed hypertension, to compare the antihypertensive activity with that of authentic GABA. The elevation of systolic blood pressure in SHRs was significantly retarded in the GABA-tempeh group as well as that with authentic GABA when compared with the controls, and the effect lasted for two months of the feeding period. The blood urea nitrogen level tended to be higher in the control group than in the GABA-supplemented groups. On the other hand, no effect was apparent on the plasma levels of cholesterol, triacylglycerol and glucose, or on the urinary excretion of Na and K.     

Consumption of hypoallergenic flour prevents gluten-induced airway inflammation in Brown Norway rats

Brown Norway rats were immunized with gluten, and then fed a diet containing hypoallergenic flour or an amino acid mixture. The rats were then made to inhale a solubilized gluten to induce gluten-specific bronchial asthma. The antibody levels in the serum of rats were measured by ELISA, and cell counts were done on cytospin preparations of bronchoalveolar lavage fluid. Body weight was decreased after allergen challenge in rats fed the amino acid mixture but not in rats fed the hypoallergenic flour. Antibody levels in the serum were significantly lower in rats fed hypoallergenic flour than in those fed the amino acid mixture. Differential cell counts in the bronchoalveolar lavage fluid showed that the numbers of eosinophils, lymphocytes, and neutrophils were significantly lower in rats fed the hypoallergenic flour than in those fed the amino acid mixture. These results suggest that hypoallergenic flour actively suppresses the allergic reactions, probably by inducing oral tolerance.     

Liver and plasma copper concentrations in rats fed diets containing various proteins

The question was addressed whether the type of dietary protein influences copper (Cu) concentrations in liver and plasma of rats. For this purpose, weanling female rats were fed diets containing as the sole source of protein either soybean protein, casein, amino acid mixtures simulating soybean protein or casein, lactalbumin, ovalbumin, or herring meal. The diets were balanced for residual Cu in the protein preparations. The type of protein and the composition of the amino acid mixture did not differentially influence liver Cu concentrations. Liver Cu was significantly lowered after feeding the amino acid mixtures when compared with the intact proteins. Plasma Cu concentrations were not affected by the type of protein in the diet.     

Chronic ethanol feeding inhibits plasma levels of insulin-like growth factor-1

The purpose of this study was to determine whether the generalized catabolic effects of chronic ethanol may be associated with a decline in plasma levels of insulin-like growth factor-1 (IGF-1). Male Sprague-Dawley rats were fed a liquid diet containing 5% ethanol or pair-fed a diet made isocaloric with maltose-dextrin. Animals were maintained on this diet for either 12 days or 4.5 months. Another group of animals were fed control diet ad libitum for 2 weeks. After 12 days of feeding, plasma concentrations of IGF-1 in ad libitum fed rats were 771 +/- 41 ng/ml which was greater than concentrations in either pair-fed (595 +/- 23 ng/ml) or ethanol-fed (680 +/- 40 ng/ml) rats (P less than 0.05). After 4.5 months of feeding, plasma levels of IGF-1 in ad libitum and pair-fed rats were similar to the 12 day study (736 +/- 56 and 607 +/- 26 ng/ml, respectively). However, a significant decrease in plasma levels of IGF-1 was observed in ethanol-fed animals over the 4.5 month period (551 +/- 28 ng/ml, P less than 0.05). Results of a similar study in rats fed a high-fat diet for 4.5 months were similar to those found with the low-fat diet. These results indicate that 1) dietary restriction of the type routinely used in this pair-feeding regimen decreases plasma levels of IGF-1, 2) chronic ethanol feeding further decreases plasma IGF-1 levels compared to pair-fed rats, 3) the effects of ethanol on IGF-1 concentrations are not modified by dietary fat, and 4) the effects on IGF-1 are not directly dependent on elevated plasma ethanol concentrations. Our results suggest that IGF-1 secreting cells in the liver may be progressively damaged by chronic ethanol feeding.     

Post-alighting responses of Mexican fruit flies (Dipt., Tephritidae) to different insecticides in paint on attractive spheres

Abstract: Two new, comparatively safe insecticides (spinosad and imidacloprid) were compared with dimethoate (each at 1.5% active ingredient) for behavioural and mortality effects on Mexican fruit flies, Anastrepha ludens . Insecticide was mixed with sugar (as a feeding stimulant) and yellow latex paint (as an extending agent) applied to the surface of fruit-mimicking biodegradable 7 cm spheres made of sugar, flour and glycerin. Flies feeding on spinosad-treated spheres did not differ from flies feeding on untreated spheres in post-feeding intra-tree flight capability, amount of oviposition or mortality. Flies that fed on imidacloprid- or dimethoate-treated spheres for as little as 30 s experienced both high reduction in oviposition and high mortality compared with flies that fed on untreated spheres, and the flies from imidacloprid-treated spheres also showed a much reduced intra-tree flight capability. If baited with attractive odour, biodegradable yellow spheres treated with a surface coating of imidacloprid in latex paint and sugar could have potential for suppressing Mexican fruit flies on host trees.     

Mineral supplementation of white wheat flour is necessary to maintain adequate mineral status and bone characteristics in rats

This experiment was designed to compare the effect of ingestion of a wheat flours on mineral status and bone characteristics in rats. White flour was tested either without further mineral supplementation or with Mg, Fe, Zn and Cu supplementation. The flour diets were compared to a control purified diet. Four groups of 10 male Wistar rats each were fed one of the experimental diets for 6 wk and mineral status and tissue retention as well as bone characteristics were determined. As expected, mineral intake, except for calcium, was significantly lesser in rats fed the white flour diet than in the other groups. The rats fed the white flour diet had the lowest food intake, weight gain, fecal excretion and intestinal fermentation. The most important result was that Mg and Fe status were drastically lower in rats fed the white flour diet than in those fed whole flour or control diets. The status of these both elements were significantly improved by the mineral supplementation of white flour. There were no major significant differences between mineral-supplemented white flour and whole flour groups in mineral status. Furthermore, bone mineral densities (total, metaphyseal and diphyseal) were significantly lower in rats fed white flour diet compared to the other diet groups, while no significant difference was observed between the mineral-supplemented white flour, whole flour or control diet groups. In conclusion, the present work shows clearly the importance of mineral-supplementation of white wheat flour to sustain an adequate intake of minerals. Our results indicate also that the whole wheat flour did not negatively alter mineral bioavailability, in comparison to mineral supplemented white flour. Clinical studies are still needed to confirm these rat results in human.     

Proteins adsorbed to a hydrophobic surface used for determination of proteolytic activity

Wettability of a thin layer of protein adsorbed to a hydrophobic surface is reduced after proteolytic digestion. Reduced wettability is demonstrated by condensation of water vapour on the surface. The condensation patterns of enzyme-treated and untreated protein layers give different light-scattering properties which can be observed by the naked eye. Based on these principles, a new simple and inexpensive method, thin layer enzyme assay (TEA), for determination of proteolytic activity, was developed. Fibrinogen, gammaglobulin (IgG), bovine serum albumin (BSA), haemoglobin, ovalbumin and gelatin were used as substrates. The proteolytic activity in 1 ng trypsin (EC 3.4.21.4) and in 1 ng pronase (EC 3.4.24.4) was reproducibly detected.     

Soybean amplifies the hypohomocysteinemic effect of betaine and improves its hypercholesterolemic effect

Abstract

We examined whether soybean (SB) and soy protein isolate (SPI) can prevent the betaine-induced elevation of plasma cholesterol as well as maintain the betaine-induced reduction of plasma Hcy concentration. Rats were fed casein-, SB-, or SPI-based diet with or without betaine; SPI-based diet with betaine containing soybean fiber (SF) or soy lecithin (SL) or the combination of SF and SL. Plasma Hcy concentration was decreased by feeding betaine to rats fed the casein-, SB-, and SPI-based diets. Betaine-induced elevation of plasma cholesterol was decreased by feeding the SB-based diet compared with the casein-based diet, but was not decreased by feeding the SPI-based diet. In rats fed the SPI-based diet, the increased concentration of plasma cholesterol by betaine feeding was not prevented by independent addition of SL or SF, but was prevented by a combination of SL and SF, and was associated with increased fecal excretion of bile acids.     

Physiologic estradiol levels enhance hypothalamic expression of the long form of the leptin receptor in intact rats

Estradiol is a potent hypophagic agent that reduces food intake and body weight without a concomitant fall in plasma leptin levels. We investigated whether the hypophagic effect of estradiol is mediated by stimulating POMC and/or inhibiting NPY neuronal pathways in the hypothalamus, which respectively inhibit and stimulate feeding. We examined hypothalamic gene expression of Ob-Rb, NPY, POMC, MC4-R, and AgRP in intact Wistar rats treated with estradiol for 48 hours. Food intake and body weight were reduced in estradiol-treated rats but fat mass was unchanged; plasma leptin and insulin levels were not significantly different from untreated, freely fed controls. In untreated rats that were pair-fed to match the estradiol-treated group, body weight was also reduced without changes in fat mass, although leptin and insulin levels decreased significantly. Ob-Rb expression was increased in both hypophagic groups despite serum leptin were only decreased in pair-fed animals, suggesting an estradiol-stimulating effect on Ob-Rb expression. No significant differences were found in POMC, AgRP, or MC4-R expression among any of the experimental groups. A significant but small decrease in NPY expression was also found in both hypophagic groups; this was explained by the combined effect of both surgery and reduced food intake. These results indicate that estradiol mediated hypophagia in intact rats could be brought about by an enhanced hypothalamic leptin sensitivity but is unlikely to be driven by changes in NPY or melanocortin system.     

Diurnal variations in inducibility of rat liver tyrosine aminotransferase activity.

The activity of tyrosine aminotransferase (TAT) was measured in the livers of rats which were entrained to eat for the first 2 hours of a daily 12 hour dark period (‘2+22’ schedule) and were treated with the synthetic glucocorticoid dexamethasone and with glucagon at several times of day. TAT activity in untreated animals varies diurnally with a maximum 4 to 6 hours after the beginning of feeding. In both fed and fasted rats there was a small diurnal variation in inducibility by dexamethasone: in fed rats induction was greatest near the beginning of the dark period, shortly after feeding; in fasted rats induction increased towards the end of the dark period. Glucagon induction showed a marked diurnal variation in fed rats with a decrease coincident with the decline in control TAT activity after its food-induced peak. This variation did not appear to be depemdent on food intake, however, since the decline in inducibility occurred in fasted rats at the same time as in fed rats. Co-treatment with dexamethasone did not affect the decrease in glucagon inducibility. The diurnal variation in TAT induction may reflect a diurnal rhythm in the components of the enzyme synthesizing system (e.g. in the availability of mRNA or in enzyme degradation).     

Protective effect of ascorbic acid against lipid peroxidation and oxidative damage in cardiac microsomes

Effects of feeding sucrose rich diet supplemented with and without the insulinmimetic agent vanadate for a period of six weeks were studied in rats. Sucrose diet caused hypertriglyceridemia (140% increase), hyperinsulinemia (120% increase) and significant elevations in the levels of glucose (p<0.001) and cholesterol (p<0.05) in plasma as compared to control starch fed rats. Activities of hepatic lipogenic enzymes, ATP-citrate lyase, glucose 6-phosphate dehydrogenase and malic enzyme increased by 100–150% as a result of sucrose feeding. However, glycogen content and the activities of glycogen synthase and phosphorylase in liver remained unaltered in these animals. The plasma levels of triacylglycerols and insulin in the rats fed on vanadate supplemented sucrose diet were 65% and 85% less, respectively as compared to rats on sucrose diet without vanadate. The concentrations of glucose and cholesterol in plasma and the activities of lipogenic enzymes in liver did not show any elevation in sucrose fed rats when supplemented with vanadate. These data indicate that the sucrose diet-induced metabolic aberrations can be prevented by the insulin-mimetic agent, vanadate.     

Role of luminal nutrients and endogenous GLP-2 in intestinal adaptation to mid-small bowel resection

To elucidate the role of luminal nutrients and glucagon-like peptide-2 (GLP-2) in intestinal adaptation, rats were subjected to 70% midjejunoileal resection or ileal transection and were maintained with total parenteral nutrition (TPN) or oral feeding. TPN rats showed small bowel mucosal hyperplasia at 8 h through 7 days after resection, demonstrating that exogenous luminal nutrients are not essential for resection-induced adaptation when residual ileum and colon are present. Increased enterocyte proliferation was a stronger determinant of resection-induced mucosal growth in orally fed animals, whereas decreased apoptosis showed a greater effect in TPN animals. Resection induced significant transient increases in plasma bioactive GLP-2 during TPN, whereas resection induced sustained increases in plasma GLP-2 during oral feeding. Resection-induced adaptive growth in TPN and orally fed rats was associated with a significant positive correlation between increases in plasma bioactive GLP-2 and proglucagon mRNA expression in the colon of TPN rats and ileum of orally fed rats. These data support a significant role for endogenous GLP-2 in the adaptive response to mid-small bowel resection in both TPN and orally fed rats.     

大鼠动脉粥样硬化动物模型的建立和评价

目的利用免疫损伤和高脂喂养结合的方法建立大鼠动脉粥样硬化（atherosclerosis,AS）动物模型。方法5周龄Wistar大鼠腹腔注射卵清白蛋白和尾静脉注射牛血清白蛋白佐以灌喂维生素D3,高脂饲料喂养大鼠,FeSO4加入到饮水中。检测大鼠不同时间的血脂水平、血液生化指标和病理变化。结果（1）AS模型组的TC、HDL、LDL显著高于正常对照组（6.1±2.52比1.3±0.10;2.46±1.01比1.02±0.13;3.76±1.67比0.52±0.063;P〈0.05）。（2）模型组的C反应蛋白（CRP）、心肌激酶（CK）、心肌激酶同工酶（CK-Mb）显著高于正常对照组（4.99±2.26比0.183±0.160;996.3±82.8比293.8±167.1;669.5±128.1比177.5±86.5;P〈0.05）。（3）采用HE染色发现模型组大鼠的主动脉出现斑块的沉积,而正常大鼠无病变的产生。结论该方法能够诱导大鼠产生高血脂症状,随着时间的延长心肌发生损伤,同时出现炎症症状,并在动脉壁上形成斑块。     

高淀粉膳食对血浆胰岛素、cAMP含量及组织cAMP代谢的影响

对高淀粉膳食(糖占总热量80％)对大鼠血脂、胰岛素及cAMP代谢的影响进行了研究。大鼠摄取高淀粉膳食3天,空腹血浆岛素及甘油三酯含量明显高于对照组(P<0.01;P<0.01)。6天后血浆甘油三酯含量增高近四倍(P<0.01),而血浆、肌肉和脂肪组织cAMP含量低于对照组,分别减低38％,45％和32％(P<0.05;P<0.05,0.1相似文献