Effect of High Fat Diets on Body Mass,Oleylethanolamide Plasma Levels and Oxytocin Expression in Growing Rats

Obesity prevalence in developed countries has promoted the need to identify the mechanisms involved in control of feeding and energy balance. We have tested the hypothesis that different fats present in diet composition may contribute in body weight gain and body indexes by regulation of oxytocin gene (oxt) expression in hypothalamus and Oleylethanolamide (OEA) levels in plasma. Sprague–Dawley rats were fed two high fat diets, based on corn (HCO) and extra virgin olive oil (HOO) and results were compared to a low fat diet (LF). LC‐MS/MS analysis showed an increasing trend of OEA plasma levels in HOO group, although no significant differences were found. However, body weight gain of LF and HOO were similar and significantly lower than HCO. HCO rats also had higher Lee index than HOO. Rats fed HOO diet showed higher levels of hypothalamic oxt mRNA expression, which could indicate that oxytocin may be modulated by dietary lipids.     

Long-term high animal protein diet reduces body weight gain and insulin secretion in diet-induced obese rats

BACKGROUND: The effects of a high protein diet on insulin secretion and glucose metabolism have been quite controversial. The aim of this study was to evaluate the effects of long‐term isocaloric high animal protein intake on insulin secretion in diet‐induced obese rats. RESULTS: After the experimental period (24 weeks), the high‐fat diet‐induced obese rats that were fed isocaloric high‐protein diets (HP) had lower body weight gain (P < 0.01) and lower visceral fat (P < 0.05) than normal protein (NP) rats. Fasting plasma glucagon‐like peptide‐1 (GLP‐1) was also reduced significantly (P < 0.05), as well as serum insulin levels at 5 min and 10 min by intravenous insulin releasing test. In addition, insulin mRNA and pancreatic duodenal homeodomain‐1 (PDX‐1), GLP‐1 protein expression were both markedly lower in HP rats (P < 0.05), while PDX‐1 mRNA in HP rats had no difference from NP rats. CONCLUSION: These results suggest that long‐term isocaloric high animal protein intake reduces the acute insulin response in obese rats and the decrease of insulin is associated with both reduced weight gain and inhibition of PDX‐1 expression. GLP‐1 might be a negative feedback for the balance of energy metabolism secondary to changes of body weight and visceral fat. Copyright © 2012 Society of Chemical Industry     

Marie Ménard apples with high polyphenol content and a low‐fat diet reduce 1,2‐dimethylhydrazine‐induced colon carcinogenesis in rats: Effects on inflammation and apoptosis

Inflammation may increase cancer risk, therefore, we studied whether polyphenol‐rich Marie Ménard (MM) apples with reported anti‐inflammatory activity prevent 1,2‐dimethylhydrazine (DMH)‐induced colon carcinogenesis in rats and, likewise whether high‐fat (HF) diet promoting carcinogenesis, may affect inflammation. DMH‐induced rats were fed for 15 weeks with: an HF diet (23% corn oil w/w); an HF diet containing 7.6% w/w lyophilized MM (apple diet (AD)); a low‐fat (LF) diet and an HF diet containing piroxicam (PXC) (0.01% w/w) as control. Mucin depleted foci (MDF), precancerous lesions in the colon, were dramatically reduced in the AD, LF, and PXC groups compared with the HF. Peritoneal macrophage activation, an index of systemic inflammation, was significantly decreased in the AD, LF, and PXC groups. TNF‐α, iNOS, IL‐1β, IL‐6 m‐RNA expression in the colon, as well as CD68 cells and plasmatic PGE2 were lower in the AD, but not in the LF group. Apoptosis in the MDF of both the AD and LF‐fed rats was significantly higher than in HF rats. In conclusion, AD has a strong chemopreventive effect, reducing inflammation, and increasing apoptosis, while the chemopreventive effect of the LF diet seems mediated mainly by increased apoptosis in MDF.     

Nanoparticles of chromium picolinate enhance chromium digestibility and absorption

BACKGROUND: Trivalent chromium (Cr) is a trace element that is difficult to digest and absorb. The objective of this study was to determine whether reducing organic Cr to nanometre size would increase its digestibility. RESULTS: Forty‐eight 8‐week‐old female Sprague‐Dawley rats were randomly assigned to one of four dietary treatments: (1) basal diet (control); (2) basal diet plus 300 µg kg^?1 Cr as chromium chloride (CrCl₃); (3) basal diet plus 300 µg kg^?1 Cr as chromium picolinate (Crpic); (4) basal diet plus 300 µg kg^?1 Cr as nanoparticulate Crpic (nanoCrpic). NanoCrpic was prepared from Crpic with a particle size of 55–100 nm. The experiment lasted 48 days. Cr digestibility and serum Cr concentration were 1.66 and 1.96 times greater respectively in rats fed nanoCrpic than in rats fed Crpic (P < 0.05). The average daily gain was greater in rats fed nanoCrpic or Crpic than in control rats (P < 0.05). The high‐density lipoprotein content increased while the very‐low‐density plus low‐density lipoprotein content decreased in rats fed nanoCrpic as compared with rats fed Crpic or CrCl₃ (P < 0.05). CONCLUSION: This study indicates that reducing the particle size of Crpic enhances Cr digestibility and absorption in rats and alters some blood metabolite concentrations. Copyright © 2009 Society of Chemical Industry     

Blood as a surrogate marker for tissue-specific DNA methylation and changes due to folate depletion in post-partum female mice

Scope : DNA methylation patterns are tissue specific and may influence tissue‐specific gene regulation. Human studies investigating DNA methylation in relation to environmental factors primarily use blood‐derived DNA as a surrogate for DNA from target tissues. It is therefore important to know if DNA methylation changes in blood in response to environmental changes reflect those in target tissues. Folate intake can influence DNA methylation, via altered methyl donor supply. Previously, manipulations of maternal folate intake during pregnancy altered the patterns of DNA methylation in offspring but, to our knowledge, the consequences for maternal DNA methylation are unknown. Given the increased requirement for folate during pregnancy, mothers may be susceptible to aberrant DNA methylation due to folate depletion. Methods and results : Female mice were fed folate‐adequate (2 mg folic acid/kg diet) or folate‐deplete (0.4 mg folic acid/kg diet) diets prior to mating and during pregnancy and lactation. Following weaning, dams were killed and DNA methylation was assessed by pyrosequencing^® in blood, liver, and kidney at the Esr1, Igf2 differentially methylated region (DMR)1, Igf2 DMR2, Slc39a4CGI1, and Slc39a4CGI2 loci. We observed tissue‐specific differences in methylation at all loci. Folate depletion reduced Igf2 DMR1 and Slc39a4CGI1 methylation across all tissues and altered Igf2 DMR2 methylation in a tissue‐specific manner (p<0.05). Conclusion : Blood‐derived DNA methylation measurements may not always reflect methylation within other tissues. Further measurements of blood‐derived and tissue‐specific methylation patterns are warranted to understand the complexity of tissue‐specific responses to altered nutritional exposure.     

Continuously Ingesting Fructooligosaccharide Can't Maintain Rats’ Gut Bifidobacterium at a High Level

Fructooligosaccharide (FOS) has been reported to increase Lactobacillus and Bifidobacterium populations in animal and human gut. Hence, it has been utilized to regulate the balance of gut microbiota. In this study, we compared the effects of high‐FOS (HFOS) diet on normal and obese rats’ gut Lactobacillus and Bifidobacterium, with high‐soybean‐fibers (HSF) diet as control. The results showed that the level of Bifidobacterium population substantially increased at week 4 in groups of rats fed the HFOS diet (P < 0.05), but significantly reduced to a small level at week 8 (P < 0.05); the abundance of Lactobacillus was increased in normal rats (P < 0.05), but decreased in obese rats (P < 0.05). The HSF diet did not promote the growth of Lactobacillus and Bifidobacterium in rats’ gut. The findings suggested that Bifidobacterium population could not be maintained at a high level when the rats continuously ingested the HFOS diet for 8 wk; additionally, Lactobacillus population could adapt to a relatively stable level with the consumption of HFOS diet.     

Assessment of zinc deficiency and effect of dietary carrot, amchur and onion on zinc status during repletion in zinc-deficient rats

BACKGROUND: Food acidulants, β‐carotene‐rich vegetables and sulfur compound‐rich Allium spices are known to improve zinc bioaccessibility from food grains. This animal study evaluated the positive influence of these promoters of zinc bioaccessibility on zinc status during zinc repletion in Wistar rats previously rendered zinc‐deficient by feeding a zinc‐deficient semi‐synthetic diet for 4 weeks. Groups of these zinc‐deficient animals were subsequently maintained on a zinc‐containing grain‐based diet for 2 weeks. Various experimental diets consisted of the grain‐based diet supplemented with (1) carrot, (2) onion, (3) amchur, (4) carrot + amchur and (5) onion + amchur. RESULTS: Zinc deficiency was confirmed by lower zinc concentration in tissues and bones and lower activity of zinc‐containing enzymes. Zinc concentration was 10–15% lower in serum, liver and kidney of zinc‐deficient rats. Bone weight in zinc‐deficient rats was 20% lower than that in normal rats. Activities of zinc‐containing enzymes (hepatic superoxide dismutase and alcohol dehydrogenase and serum alkaline phosphatase) were lower in the zinc‐deficient group. Animals fed diets supplemented with these promoters of zinc bioaccessibility showed better zinc status in tissues and bones compared with those repleted with the control stock diet. CONCLUSION: This animal study supports the claim of promoters of zinc bioaccessibility for improving zinc status, which may find practical application. Copyright © 2011 Society of Chemical Industry     

Anti-obesity role of adzuki bean extract containing polyphenols: in vivo and in vitro effects

BACKGROUND: The aim of this work was to evaluate the effects of polyphenol‐rich adzuki bean extract on lipid metabolism, triglyceride accumulation and proinflammatory cytokine secretion in vivo and in vitro. RESULTS: For the in vivo study, rats were divided into four groups: group C was fed a control diet, group A was fed the control diet with 1% adzuki bean extract, group CF was fed a high fat diet, and group AF was fed a high fat diet with 1% adzuki bean extract. For the in vitro study, the ability of adzuki bean extract to suppress triglyceride incorporation, glycerol phosphate dehydrogenase activity and inflammatory response was investigated in cultured human adipocytes. Data from the animal study showed that adzuki bean extract improved lipid metabolism in both the normal and high‐fat diet groups. Adzuki bean extract treatment in the high‐fat group resulted in significant reductions in total hepatic lipid accumulation and lipid secretion into the feces. Incubation of adipocytes with adzuki bean extract significantly decreased triglyceride accumulation, glycerol phosphate dehydrogenase activity and inflammatory responses without affecting cell viability. CONCLUSION: The results of this study demonstrate that adzuki bean extract has high potential to serve as a natural anti‐obesity agent. Copyright © 2012 Society of Chemical Industry     

EFFECTS OF ORAL CHONDROITIN SULFATE ON LIPID AND ANTIOXIDANT METABOLISMS IN RATS FED A HIGH-FAT DIET

This study aimed at determining the effects of purified chondroitin sulfate (ChS) from pig laryngeal cartilage on the lipid and antioxidant metabolisms of male Sprague‐Dawley rats that are fed a high‐fat diet. Thirty‐two male rats were divided into four groups and fed for 5 weeks on a standard diet, a high‐fat diet or a high‐fat diet plus ChS. It was demonstrated that the high‐fat diet provoked lipid peroxidation and induced a severe depletion of lipoprotein lipase, hepatic lipidase, glutathione, catalase and superoxide dismutase levels. ChS was effective in reducing triglycerides, total cholesterol, low‐density‐lipid cholesterol and malondialdehyde levels elevated by the high‐fat diet. In addition, ChS might reduce the risk of atherosclerosis, as high‐density‐lipid cholesterol, lipoprotein lipase, hepatic lipidase and the ratio of high‐density‐lipoprotein cholesterol to total cholesterol were significantly higher than in the high‐fat‐diet rats. ChS restored the endogenous antioxidants glutathione, catalase and superoxide dismutase. These results showed that ChS was potent in lipid‐lowering and altering the antioxidative enzyme; however, excess ChS would disturb lipid profiles that went beyond the normal limits.     

Short‐term feeding of fermentable dietary fibres influences the gut microbiota composition and metabolic activity in rats

This study investigated the effects of dietary fibres on gut bacterial abundance and metabolic activity in rats fed short‐term. Faecal samples from rats fed for 7 days showed differences in the effects of dietary fibres on gut bacterial populations. Broccoli fibre, inulin, potato fibre and potato resistant starch significantly increased the faecal Bacteroides‐Prevotella‐Porphyromonas group compared with cellulose. Growth of pathogenic bacteria such as Clostridium perfringens, Escherichia coli and Enterococcus spp. was decreased significantly in rats fed barley β‐glucan, citrus pectin, inulin and broccoli fibre diets. An increase in Bifidobacterium spp. and butyric acid levels, the so‐called bifidogenic and butyrogenic effects, was observed in rats fed inulin and potato fibre diets. Organic acid concentrations and polysaccharide contents in the rat faeces confirm the fermentability of dietary fibres in the gut. This study demonstrates the positive effects of plant‐sourced dietary fibres on gut microbiota composition and metabolic activity.     

Goldenberry (Physalis peruviana) Juice Rich in Health‐Beneficial Compounds Suppresses High‐Cholesterol Diet‐Induced Hypercholesterolemia in Rats

Goldenberries (Physalis peruviana) are a promising exotic fruit that could be a subject of many novel foods. No reports are available on the effect of administration of goldenberries on different aspects of blood profile in experimental animals. The objective of this study was to investigate the effect of feeding goldenberry juice on hypercholesterolemia by analyzing the changes in the blood profile of high‐cholesterol diet (HCD)‐fed rats. The chemical composition and antiradical properties of juice were determined. Generally, rats fed with goldenberry juice showed lower levels of total cholesterol, total triacylglycerol and total low‐density lipoprotein cholesterol, as well as higher levels of high‐density lipoprotein cholesterol in comparison with animals fed with HCD and cholesterol‐free diet. Juice administration induced a decrease in the activity of glutamic pyruvic transaminase compared with the positive control group after 2 months of administration. There was a remarkable decrease in total serum protein, albumin and globulin for groups treated with goldenberry juice. Histological examination of the liver and kidney were also conducted. The results demonstrated that consumption of goldenberry juice may provide beneficial effects on reversing HCD‐associated detrimental changes.     

The effects of sorghum proanthocyanidins on digestive enzyme activity in vitro and in the digestive tract of chicken

The effects of sorghum grain proanthocyanidins (PAs) on the digestive enzyme activity of broiler chickens were investigated in vitro and in vivo using seven sorghum varieties grown in Zimbabwe. All seven sorghum varieties, classified as either high‐PA (DC‐75, Mutode, Red Swazi and Chirimaugute) or low‐PA (SV2, Brown Tsweta and Chibonda), were used to assess the PA–protein binding capacity and inhibition of trypsin and amylase in vitro. Three of the varieties (Chirimaugute, Chibonda and Brown Tsweta) were subsequently used in broiler diets to test the effects of PAs on the growth performance and digestive enzyme activity of 48 broiler chicks at 42 days of age. Protein precipitation and trypsin and amylase inhibition increased (P < 0.05) with an increase in level of PAs from the low‐PA varieties (by 1–10%) to the high‐PA varieties (by 40–70%). The activity of trypsin in the duodenal lumen of chicks fed the control diet was almost double that of chicks fed Chirimaugute. Amylase activity in the high‐PA group was lowered significantly (P < 0.01) relative to the control and low‐PA groups. The difference between in vitro and in vivo residual enzyme activities was 10–20% for amylase and 5–10% for trypsin. Chicks fed the high‐PA diet showed lower performance than chicks fed the control and low‐PA diets. Mean body weight gains were 59.9, 34.4, 57.3 and 61.4 (SE 4.02) g day⁻¹, final weights were 1936.4, 1363.3, 1773.2 and 1857.0 (SE 78.5) g and feed efficiencies were 1.85, 2.26, 1.65 and 2.13 (SE 0.014) for the control, Chirimaugute, Brown Tsweta and Chibonda groups respectively. The results indicate that PA–enzyme interaction, in addition to dietary protein–PA binding, contributes to the poor performance of chickens fed high‐PA sorghum diets. © 2000 Society of Chemical Industry     

Effect of Trans Fatty Acids on Protein Utilization and Serum Cholesterol

Rats were fed PER diets containing various proportions of cis and trans fatty acids as triolein, trielaidin, soybean oil (SO) or hydrogenated SO at 7.8% by weight of the diet. Additional rats were fed SO or hydrogenated SO at 20.1% of the diet. The PER, although in the normal range for casein, was significantly (P < 0.01) lower in rats fed trielaidin. Food consumption and weight gains were slightly greater in trans-fed than cis-fed rats. The former had greater fecal fat excretion than the latter; serum cholesterol levels of the former were lower with the 7.8% but not the 20.1% fat diet.     

Digestive utilisation of protein and amino acids from raw and heated lentils by growing rats

The effect of autoclave treatment on the digestive utilisation of protein and amino acids from lentils was studied in growing rats. Twenty 3‐week‐old Wistar rats (mean live weight 59 ± 4.8 g) were fed two experimental diets (n = 10 rats per diet) consisting of raw lentils (Lens culinaris M, var vulgaris, cv magda‐20) (diet RL) or lentils autoclaved at 120 °C and 1 atm for 30 min (diet AL). An additional group of 10 animals was fed a low‐protein (4%) diet and used to estimate metabolic nitrogen and amino acid excretion. Autoclaving caused a 76% reduction in the levels of trypsin inhibitor activity, but failed to improve the faecal digestive utilisation of protein or total amino acids. Lowest essential amino acid true digestibility in diets RL and AL was found for cysteine (60.2 vs 60.1%) and methionine (68.9 vs 66.6%). The protein digestibility‐corrected amino acid score was 71.2 and 66.4% and the availability of sulphur amino acid‐corrected amino acid score was 57.1 and 52.1% for diets RL and AL respectively. Sulphur amino acids were the first limiting ones. Overall, autoclave treatment did not improve protein or total amino acid digestibility from lentils, but caused a significant improvement in leucine and lysine digestibility and a significant decrease in the digestive utilisation of tyrosine and methionine. © 2002 Society of Chemical Industry     

Effects of Potato Fiber and Potato‐Resistant Starch on Biomarkers of Colonic Health in Rats Fed Diets Containing Red Meat

Abstract: The effects of red meat consumption with and without fermentable carbohydrates on indices of large bowel health in rats were examined. Sprague‐Dawley rats were fed cellulose, potato fiber, or potato‐resistant starch diets containing 12% casein for 2 wk, then similar diets containing 25% cooked beef for 6 wk. After week 8, cecal and colonic microbiota composition, fermentation end‐products, colon structure, and colonocyte DNA damage were analyzed. Rats fed potato fiber had lower Bacteroides‐Prevotella‐Porphyromonas group compared to other diet groups. Colonic Bifidobacterium spp. and/or Lactobacillus spp. were higher in potato fiber and potato‐resistant starch diets than in the cellulose diet. Beneficial changes were observed in short‐chain fatty acid concentrations (acetic, butyric, and propionic acids) in rats fed potato fiber compared with rats fed cellulose. Phenol and p‐cresol concentrations were lower in the cecum and colon of rats fed potato fiber. An increase in goblet cells per crypt and longer crypts were found in the colon of rats fed potato fiber and potato‐resistant starch diets. Fermentable carbohydrates had no effect on colonic DNA damage. Dietary combinations of red meat with potato fiber or potato‐resistant starch have distinctive effects in the large bowel. Future studies are essential to examine the efficacy of different types of nondigestible carbohydrates in maintaining colonic health during long‐term consumption of high‐protein diets. Practical Application: Improved understanding of interactions between the food consumed and gut microbiota provides knowledge needed to make healthier food choices for large bowel health. The impact of red meat on large bowel health may be ameliorated by consuming with fermentable dietary fiber, a colonic energy source that produces less harmful by‐products than the microbial breakdown of colonic protein for energy. Developing functional red meat products with fermentable dietary fiber could be one way to promote a healthy and balanced macronutrient diet.     

Inhibitory effects of Hibiscus sabdariffa L extract on low‐density lipoprotein oxidation and anti‐hyperlipidemia in fructose‐fed and cholesterol‐fed rats

Hibiscus sabdariffa L extract (HSE) is an aqueous extract of Hibiscus sabdariffa L flowers that is used as a local soft drink and medical herb in Taiwan. Oxidation of low‐density lipoprotein (LDL) has been shown to increase the incidence of atherosclerosis. In this study, we determined the antioxidative activity of HSE on LDL oxidation by examining relative electrophoretic mobilities (REM) and thiobarbituric acid‐reactive substances (TBARS). The data revealed an inhibitory effect of HSE on Cu²⁺‐mediated REM and TBARS. HSE exhibited a remarkable ability to reduce cholesterol degradation and ApoB fragmentation. Overall, HSE showed a high potency to inhibit the production of oxidized LDL induced by copper and, specifically, to reduce serum triglycerides in high‐fructose diet (HFD) fed rats and serum cholesterol in high‐cholesterol diet (HCD) fed animals. The levels of LDL and the ratio of LDL‐cholesterol (LDL‐C) to HDL‐cholesterol (HDL‐C) were reduced by HSE in both hyperlipidaemia models. Based on these findings, we suggest that HSE may be used to inhibit LDL oxidation and to prevent various types of hyperlipidaemia in HFD‐ or HCD‐fed rats. Copyright © 2004 Society of Chemical Industry     

Effect of Dietary Partial Hydrolysate of Phospholipids,Rich in Docosahexaenoic Acid‐Bound Lysophospholipids,on Lipid and Fatty Acid Composition in Rat Serum and Liver

Lysophospholipids have been recognized as potent biologically active lipid mediators. However, attention has not been paid to the health benefits of dietary partial hydrolysate of phospholipids (PH‐PL), which is rich in docosahexaenoic acid (DHA)‐bound lysophospholipids. In this study, the effects of PH‐PL on serum and liver lipid profiles of rats upon administration of PH‐PL are demonstrated in comparison to those of fish oil (FO), which comprises eicosapentaenoic acid (EPA) and DHA‐bound triglyceride (TG). PH‐PL containing EPA and DHA was prepared via enzymatic modification of squid (Todarodes pacificus) meal that is rich in phospholipids. Male Wistar rats were fed a basal diet containing soybean oil alone (7%), FO, and PH‐PL. The FO and PH‐PL diets had similar EPA and DHA contents. After the rats had been fed their respective diets for 28 d, their serum and liver lipid contents, fecal lipid excretion, and hepatic gene expression level were measured. The results demonstrated that compared with the soybean oil diet alone, the PH‐PL diet decreased serum and liver TG contents partially because of the enhancement of liver acyl‐CoA oxidase activity and suppression of liver fatty acid synthase activity. In addition, compared with the soybean oil diet, the PH‐PL group exhibited lower serum cholesterol content at least in part because of the reduction of hepatic 3‐hydroxy‐3‐methylglutaryl‐CoA reductase mRNA expression level. We found that dietary administration of EPA and DHA containing PH‐PL has a hypolipidemic effect that may help prevent the development lifestyle‐related diseases.     

Effect of dietary lipid sources on odour‐active compounds in muscle of turbot (Psetta maxima)

Odour‐active compounds in muscle of turbot (Psetta maxima) fed experimental diets containing fish oil (FO), soybean oil (SO) or linseed oil (LO) were investigated by a gas chromatography/olfactometry technique. Thirty‐one areas associated with odours were detected in muscle extracts. Among the compounds responsible for these odours, 23 were formed by oxidation of unsaturated fatty acids. Independently of diet, (E)‐2‐penten‐1‐ol and (E)‐3‐hexen‐1‐ol contribute strongly to the odour of turbot. (E,Z)‐2,6‐Nonadienal, (E)‐2‐pentenal and (E,E)‐1,3‐(Z)‐5‐octatriene seem to contribute strongly to the odour of turbot fed diets containing high levels of n‐3 PUFA (FO and LO groups). Hexanal and decanal show a high detection frequency in turbot fed diets containing vegetable oils. Odorous compounds which are not formed by lipid oxidation (methional, 1‐acetyl pyrazine, 4‐ethyl benzaldehyde and 2‐acetyl‐2‐thiazoline) were not affected by dietary lipid sources. © 2001 Society of Chemical Industry