Impact of grape pomace consumption on the blood lipid profile and liver genes associated with lipid metabolism of young rats.

Herein, we investigated the effects of grape pomace (GP) in diet on body weight, blood lipid profile, and expression of liver genes associated with lipid metabolism using a young rat model. In this study, twenty female Sprague-Dawley rats at 7 weeks of age were randomly divided into 4 groups, which were fed modified AIN-93G diets containing 0% (control), 6.9%, 13.8%, and 20.7% of GP for 10 weeks. Feed consumption and body weight were weekly determined. Blood samples were obtained at the beginning and end of the feeding period for cholesterol, alanine aminotransferase (ALT), and glucose analysis. At the end of the feeding period, all rats were fasted overnight and euthanized. Heart, kidney, and liver samples were obtained and weighed. Liver tissues were used for gene expression analysis. GP-containing diet did not influence the body weight of the rats. As GP content increased, blood triglyceride and very low density lipoprotein (VLDL) decreased (P < 0.05), high density lipoprotein (HDL) slightly increased but was not statistically significant, total cholesterol (TC) and low density lipoprotein (LDL) significantly increased (P < 0.05), blood glucose decreased, and ALT level slightly increased. The expressions of liver genes associated with fatty acid synthesis and lipid hydrolysis/metabolism were moderately downregulated by the GP diet. The study suggests that regular consumption of a diet containing appropriate amount of GP may help in the reduction of body fat accumulation and prevention of obesity. This is the first study revealing the change in gene expression caused by long-term consumption of GP-containing diet.

Impact of Diet Containing Grape Pomace on Growth Performance and Blood Lipid Profile of Young Rats.

Grape pomace (GP), the residue of grapes after wine making, is rich in dietary polyphenols and fiber, and it has potential to serve as a functional food ingredient to improve health. However, high polyphenol diets have also been reported to inhibit the growth of young animals and cause liver necrosis. This study investigated the effect of diets containing different amounts of GP on the growth performance and blood lipid profile by using a young rat model. Twenty female Sprague-Dawley rats of age 7 weeks were randomly divided into four groups that were fed AIN-93G diets that were modified by substituting 0%, 10%, 20%, and 30% of carbohydrate with GP for 10 weeks (the diets, thus, obtained contained 0%, 6.9%, 13.8%, and 20.7% of GP). The group fed original AIN-93G (0% GP) was used as control. Feed consumption, body weight, length, and height were recorded weekly. Blood samples were taken biweekly to analyze plasma lipid profile. At the end of the feeding period, the rats were fasted overnight and euthanized by exsanguination under anesthesia. Livers, hearts, and kidneys were collected, and their weights were recorded. Results show that the diet containing a maximum of 20.7% of GP did not influence the body weights, lengths, and heights of rats. As the GP content increased, the blood triglyceride and very low-density lipoproteins (VLDL) decreased, the high-density lipoprotein (HDL) and low-density lipoprotein (LDL) increased slightly but were statistically significant, and total cholesterol remained constant. In conclusion, GP in the AIN-93G diet did not influence the growth performance of young rats, but it exhibited both positive and negative effects on the blood lipid profile.

Bioavailability of polyphenols from peanut skin extract associated with plasma lipid lowering function.

Peanut skin is a rich source of polyphenols including procyanidins and is shown to have hypolipidemic properties. This study investigated the bioavailability of peanut skin polyphenols using a rat model. First, the bioavailability of peanut skin polyphenols in rat plasma was evaluated. Our results showed procyanidin A2 levels in plasma peaked within 30 min of ingestion. The results of a second study show that peanut skin extract supplemented in addition to oil gavage resulted in significant decrease in plasma triglyceride and VLDL within 5h. In the third study, rats were given a Western type diet for 5 weeks with peanut skin extract at a dose of 150 and 300 mg/kg body weight. The main effects observed were lowering of total blood lipid and reduction of the plasma fatty acids profile. Our results suggest that procyanidin A may impart a key role of hypolipidemic effect seen in peanut skin polyphenols.

Evaluation of hypolipidemic effects of peanut skin-derived polyphenols in rats on Western-diet.

The effect of water soluble polyphenolic extract of peanut skin (PE) was investigated for its hypolipidemic properties in rats on Western diet. Seven-weeks old Wistar rats received control diet (AIN-93G), Western diet with and without a bolus of PE five times a week for 10weeks. Group which received 300mg/kg body weight showed significantly reduced body weight and epididymal fat. Plasma and liver triglyceride (TG) and cholesterol (TC) levels were significantly reduced while faecal secretion of TG and TC was greatly increased upon PE administration. Liver mRNA expression of enzymes involved in fatty acid synthesis, such as fatty acid synthase (FAS), sterol receptor element binding protein (SREBP)-1c, acetyl-CoA carboxylase (ACC1) and lipid uptake genes, such as PPARγ, were decreased, while PPARα was up-regulated by administration of PE. These data suggest that administration of PE may contribute to the improved lipid homoeostasis in rats on diets high in cholesterol and lipids.