Rinaldo Cardoso dos Santos

Dietary models for inducing hypercholesterolemia in rats

The present work aimed at finding a dietetical model capable of promoting the highest hypercholesterolemia without affecting the development of the rats. Sixty female Fisher rats were divided into five groups. The first one was fed a control diet; the remaining four were fed hypercholesterolemic diets with cholesterol and different contents of soybean oil, starch, casein, micronutrients and fiber and, consequently, different caloric values. After eight weeks animals were evaluated in relation to growth, fecal excretion, liver weight and fat, cholesterol and its fractions, serum biochemical parameters and sistolic pressure and compared with controls. The best result was obtained with the diet containing 25 % soybean oil, 1.0 % cholesterol, 13 % fiber and 4,538.4 Kcal/Kg, since it promoted an increase in LDL-cholesterol, a decrease in the HDL fraction and affected less the hepatic function of the animals.

Clastogenic effect of bracken fern (Pteridium aquilinum v. arachnoideum) diet in peripheral lymphocytes of human consumers: preliminary data

Ingestion of bracken fern (Pteridium aquilinum v. arachnoideum) is associated with digestive tract cancer in different regions of Japan, Venezuela and Brazil. In view of reports that dietary bracken fern causes chromosomal instability in cattle, the clastogenic effect of bracken fern was investigated, in a preliminary study, in peripheral lymphocytes obtained from habitual consumers and a control group of non-consumers, which were carefully investigated about cancer history or family cancer history, negative in both cases, using protocols comparable to those previously described in studies in cattle raised on bracken pastures. Cytogenetic analysis showed significant increased levels of chromosomal abnormalities, such as chromatid breaks, in cultured peripheral lymphocytes of the consumer group. There was no correlation with subjects, gender, smoking habits or alcohol consumption, and the only correlation was with prolonged exposure to dietary bracken.

Effect of an aqueous extract of annatto (Bixa orellana) seeds on lipid profile and biochemical markers of renal and hepatic function in hipercholesterolemic rats

Annatto extract is a natural food color obtained fr om the outer coatings of the seeds of the Annatto t ree ( Bixa orellana L.). This is the first report in the literature that shows the relationship between the aqueous annat to extract and its influence on lipid profile in animals. Male Fisher rats were divided into three groups (n=12): C group, fed standard diet and water; H group, fed high-lipid di et and water and; HU group, with high-lipid diet an d aqueous annatto extract for 60 days. The treatment with ann atto extract in animals fed with the high-lipid die t lowered the LDL- and total cholesterol and raised the HDL-chole sterol, suggesting a hypocholesterolemic effect. Ne ither highfat diet nor aqueous annatto extract had any signif icant effect on serum levels of albumin or serum ac tivities of transaminases which suggested that no liver injury was induced.

Effect of aubergine (Solanum melongena) on serum and hepatic cholesterol and triglycerides in rats

The present work reports the effect of aubergine extract on serum and hepatic cholesterol and triglycerides levels in adult rats. Fisher rats were divided into three groups: the first one received a normolipidic diet and water , serving as a control; the other two received a hypercholesterolaemic diet with 30% vegetable oil and 1% cholesterol, one of these being given water while the other was given an aubergine extract. After 28 days the animals were sacrificed and serum and hepatic cholesterol and triglycerides levels were assessed. The obtained results indicated that under the experimental conditions employed, the aubergine extract increased serum and decreased hepatic cholesterol and had little or no effect on both serum and hepatic triglycerides.

Evaluation of Biological and Biochemical Quality of Whey Protein

Nutritional and biochemical properties of noncommercial whey protein have been described since 1950. However, comparisons between commercial whey protein for human consumption and casein are rarely found. The aim of this study was to compare biological quality of a commercial whey protein with casein and its effect on biochemical parameters of rats. Thirty-two weanling Fisher rats were divided into three groups and given the following diets: casein group, standard diet (AOAC); whey protein group, modified AOAC diet with whey protein instead of casein; and casein:whey group, modified AOAC diet with 70%:30% casein:whey. A protein-free group was used for determination of endogenous nitrogen losses. Net protein ratio, protein efficiency ratio, and true digestibility were determined, and blood was collected for biochemical analysis. When compared with casein, whey protein showed significant differences for all biological parameters evaluated, as well as for albumin, total protein, total cholesterol, and glucose concentrations. Replacing 30% of casein with whey protein did not affect these parameters. A positive relation among whey protein, high-density lipoprotein-cholesterol, and paraoxonase activity was found. Hepatic or renal dysfunctions were not observed. In conclusion, in comparison with casein, commercial whey protein had higher values of biological parameters, and biochemical evaluation revealed it improved glycemic homeostasis, lipid status, and paraoxonase activity in rats.

Influência das proteínas do soro sobre enzimas hepáticas, perfil lipídico e formação óssea de ratos hipercolesterolêmicos

OBJECTIVE: The aim of this study was to assess the effect of whey protein consumption on the lipid, hepatic and renal metabolism, bone formation and antioxidant defense system of rats given a hypercholesterolemic diet. METHODS: A total of 32 adult Fisher rats were divided into 4 groups: C group, standard diet; H group, hypercholesterolemic diet; WP group, standard diet with whey protein; WPH group, hypercholesterolemic diet with whey protein. Food ingestion and weight gain were monitored weekly. After 8 weeks, blood was collected for biochemical analysis and the rats were killed. The statistical tests analysis of variance and Tukeys test were performed. RESULTS: Whey protein did not lower serum cholesterol significantly and increased serum triglycerides in hypercholesterolemic rats. However, whey protein decreased the activity of aspartate aminotransferase and alkaline phosphatase, as well as serum creatinine. The assessed antioxidant defenses were not affected. Diets containing whey protein generated heavier, thicker and longer bones than casein diets. CONCLUSION: Whey proteins did not have a significant hypocholesterolemic effect in rats. On the other hand, they significantly prevented changes in liver and kidney functions brought about by hypercholesterolemic diets. Data also suggest that whey proteins benefit bone formation when compared with casein diets.

High dietary salt decreases antioxidant defenses in the liver of fructose-fed insulin-resistant rats

In this study we investigated the hypothesis that a high-salt diet to hyperinsulinemic rats might impair antioxidant defense owing to its involvement in the activation of sodium reabsorption to lead to higher oxidative stress. Rats were fed a standard (CON), a high-salt (HS), or a high-fructose (HF) diet for 10 weeks after which, 50% of the animals belonging to the HF group were switched to a regimen of high-fructose and high-salt diet (HFS) for 10 more weeks, while the other groups were fed with their respective diets. Animals were then euthanized and their blood and liver were examined. Fasting plasma glucose was found to be significantly higher (approximately 50%) in fructose-fed rats than in the control and HS rats, whereas fat liver also differed in these animals, producing steatosis. Feeding fructose-fed rats with the high-salt diet triggered hyperinsulinemia and lowered insulin sensitivity, which led to increased levels of serum sodium compared to the HS group. This resulted in membrane perturbation, which in the presence of steatosis potentially enhanced hepatic lipid peroxidation, thereby decreasing the level of antioxidant defenses, as shown by GSH/GSSG ratio (HFS rats, 7.098±2.1 versus CON rats, 13.2±6.1) and superoxide dismutase (HFS rats, 2.1±0.05 versus CON rats, 2.3±0.1%), and catalase (HFS rats, 526.6±88.6 versus CON rats, 745.8±228.7 U/mg ptn) activities. Our results indicate that consumption of a salt-rich diet by insulin-resistant rats may lead to regulation of sodium reabsorption, worsening hepatic lipid peroxidation associated with impaired antioxidant defenses.

Biological evaluation of a nutritional supplement prepared with QPM Maize cultivar BR 473 and other traditional food items

Quality Protein Maize (QPM) cultivar BR 473 was emp loyed, together with soybean flour, brown sugar, ba nana meal and oat meal, for the preparation of a nutriti onal supplement.. 21-day old male Fisher rats were fed diets containing the supplement as a protein source, both with and without soybean flour; casein diets with 10 or 7% protein served as respective controls. Protein Effi ciency Ratio (PER), Net Protein Utilization (NPU), Net Protein Retention (NPR) and Digestibility were determined. Blood biochemical parameters (glucose, cholesterol, urea, hemoglobin, albumin and total protein) were also me asured in the animals and showed that all were in g ood health condition at the end of the experiment. The obtaine d results for PER, NPU and NPR indicated that the s prepared with QPM maize cultivar BR 473 was a good protein source, especially when soybean flour was a dded.

Whey protein improves HDL/non-HDL ratio and body weight gain in rats subjected to the resistance exercise

The aim of this study was to evaluate the effects o f resistance exercise, such as weight-lifting (WL) on the biochemical parameters of lipid metabolism and card iovascular disease risk in the rats fed casein (control) or whey protein (WP) diets. Thirty-two male Fisher rats wer e randomly assigned to sedentary or exercise-traine d groups and were fed control or WP diets. The WL program co nsisted of inducing the animals to perform the sets of jumps with weights attached to the chest. After seven wee ks, arteriovenous blood samples were collected for analysis. The WL or WP ingestion were able to improve the lipid p rofile, reducing the TC and non-HDL cholesterol concentrations, but only WP treatment significantly increased the serum HDL concentrations, thereby al so affecting the TC/HDL and HDL/non-HDL ratios. However, WL plus WP was more effective in improving the HDL/non-HDL ratio than the exercise or WP ingestion alone and t he body weight gain than exercise without WP ingest ion.

Biological evaluation of crude and degummed oil from Moringa oleifera seeds

The aim of this work was to evaluate the oil extrac ted from Moringa oleifera (fam. Moringaceae) seeds from the nutritional standpoint. Nutritional evaluation of crude or degummed moring a oil or soybean oil (as a control) involved the determination of the Food Efficiency ( FE) in male Fisher rats and the fatty acid composit ion of the moringa oil. Hepatic and renal functions were asses sed by measuring serum transaminases activity and u rea and creatinine concentrations, respectively. Serum chol esterol and triglycerides, alkaline phosphatase, to tal proteins and albumine were also measured. Results showed tha t FE was slightly increased by the crude moringa oi l while no differences were found between the soybean and degu mmed moringa oil regarding this parameter. Renal or hepatic injures as well as major alterations in serum prote ins were not induced by the tested oils. These resu lts suggested that degummed M. oleifera oil possessed adequate biological quality as compa red to the crude oil.