Effects of a chitosan intake on the fecal excretion of dioxins and fat in rats

We evaluated the effects of the intake of various dietary fibers on the fecal excretion of dioxins in rats. The rats were fed five types of dietary fiber diets, including a chitosan diet and control diet, for 20 d and then dioxins (120 ng/rat) were orally administered on day 15. The excretion of fecal dioxins was significantly higher in the chitosan group than in the control group, and dioxin excretion was positively correlated with fecal fat excretion. A comparison of the different types of chitosan showed that the efficacy of chitosan for fecal fat excretion was partly related to its viscosity. The chitosan intake promoted fecal dioxin excretion when the rats were exposed to highly toxic dioxins, and this excretion of fecal dioxins was related to the fecal fat excretion, suggesting that chitosan might be useful for reducing the adverse effects caused by lipophilic xenobiotics.     

Decreasing Effect of Chitosan on the Apparent Fat Digestibility by Rats Fed on a High-fat Diet

We investigated the effects of various dietary fibers or their likenesses on the apparent fat digestibility by rats fed on a high-fat diet. Each of 23 different fibers was added at 5% (w/w) to a purified diet containing 20% (w/w) corn oil. The rats were fed these diets for 2 weeks, and the feces were collected from each animal during the last 3 days. When compared with cellulose (control), 10 of the tested fibers significantly increased the fecal lipid excretion. Among these fibers, chitosan markedly increased the fecal lipid excretion and reduced the apparent fat digestibility to about a half relative to the control. The apparent protein digestibility was not greatly affected by chitosan. The fatty acid composition of the fecal lipids closely reflected that of the dietary fat. These results suggest that chitosan has potency for interfering with fat digestion and absorption in the intestinal tract, and for facilitating the excretion of dietary fat into the feces.     

Effect of chitosan intake on fecal excretion of dioxins and polychlorinated biphenyls in healthy men

Six healthy male subjects were treated with 0 g, 1 g, 3 g, and 0 g of chitosan for the first, second, third, and fourth of four weeks, respectively. They were administered chitosan before breakfast on the second, third, and fourth days of the week, and fecal specimens were collected corresponding to the prescribed diet consumed for breakfast on the second day to breakfast on the fourth day. Fecal excretion of dioxins and polychlorinated biphenyls (PCBs) was promoted by intake of 3 g of chitosan (p=0.0589 and p<0.05 respectively), and was positively correlated with that of fat (p<0.01 for both). We found that chitosan intake increased the fecal excretion of dioxins and PCBs, as well as that of fat, suggesting that it might be useful for reducing the adverse effects of lipophilic endocrine-disrupting chemicals.     

Comparative Evaluation of Fecal Fat Excretion Induced by Orlistat and Chitosan

Objective: To compare the effects of chitosan and orlistat on fecal fat excretion. Research Methods and Procedure: A randomized, open‐label, two‐period sequential design study was used. A total of 12 healthy adult volunteers within 20% of their ideal body weight entered a 7‐day run‐in diet period before being randomized to orlistat (120 mg) or chitosan (890 mg) three times daily for 7 days. Subjects then crossed over treatment regimens for an additional 7‐day period. Subjects followed a standardized diet (2500 kcal/d, 30% as fat) for the entire 21‐day study. Feces were collected on days 4 to 7 of the run‐in period (baseline) and during the two treatment periods. Mean daily fecal fat excretion was measured at baseline and during each treatment regimen. Results: Mean baseline fecal fat excretion for all subjects was 1.36 ± 0.45 g/d. During orlistat treatment, mean fecal fat excretion significantly increased from baseline (+16.13 ± 7.27 g/d; p < 0.001). No significant effect was observed with chitosan (+0.27 ± 1.02 g/d; p = 0.379). Fecal fat excretion was significantly greater with orlistat than with chitosan (p < 0.001; 95% confidence intervals: 11.73; 20.00 g/d). Discussion: This study provides additional evidence of the inhibitory effect of orlistat on dietary fat absorption. Chitosan, however, has no effect on fecal fat excretion.     

High Dietary Calcium Reduces Body Fat Content,Digestibility of Fat,and Serum Vitamin D in Rats

Objective: This study investigated which aspect of energy balance was responsible for the decrease in body fat content of rats fed a high‐calcium, high—dairy protein diet. Research Methods and Procedures: Male Wistar rats were fed a control diet (25% kcal fat, 14% kcal protein from casein, 0.4% by weight calcium) or high‐calcium diet (25% kcal fat, 7% kcal protein from nonfat dry milk, 7% kcal protein from casein, 2.4% calcium) for 85 days. Body weights, digestible energy intakes, energy expenditures, rectal temperatures, body composition, and serum glucose, insulin, free fatty acids, triglycerides, and 1, 25‐dihydroxyvitamin D were measured. Results: Rats fed high‐calcium diet gained significantly less weight than controls and had 29% less carcass fat. Gross energy intake was not significantly different between groups, but digestible energy was 90% of gross energy in the high‐calcium diet compared with 94% in the control diet because of increased fecal excretion of dietary lipid. The difference in digestible energy intake accounted for differences in carcass energy. Body temperatures and energy expenditures of the rats were not different. The high‐calcium diet reduced serum triglycerides by 23% and serum 1, 25‐dihydroxyvitamin D by 86%. Discussion: These results confirm that a high‐calcium diet decreases body weight and fat content due to a lower digestible energy intake caused by increased fecal lipid and a nonsignificant reduction in gross energy intake.     

Stimulation of fecal fat excretion and the disposal of protoporphyrin in a murine model for erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is characterized by toxic accumulation of the hydrophobic compound protoporphyrin (PP). Ferrochelatase-deficient (fch/fch) mice are an animal model for human EPP. Recently, we have demonstrated that the accumulation of another hydrophobic compound, unconjugated bilirubin, could effectively be treated by stimulation of fecal fat excretion. We investigated whether stimulation of fecal fat excretion enhanced the disposal of PP in fch/fch mice. Fch/fch mice were fed for 8 wk with a high-fat diet (16 wt% fat; control) or with the high-fat diet mixed with either a nonabsorbable fat (sucrose polyester) or the intestinal lipase inhibitor orlistat. The effects of the treatments on fecal excretion of fat and PP and on hepatic PP concentrations were compared with control diets. Fecal fat excretion in fch/fch mice on a high-fat diet was higher than in mice on a low-fat diet (+149%, P < 0.05). Sucrose polyesters and orlistat increased fecal fat excretion even more, up to sixfold of control values. However, none of the different treatments affected fecal PP excretion or hepatic PP concentration. Treatment of fch/fch mice with a high-fat diet, a nonabsorbable fat diet, or with orlistat increased the fecal excretion of fat but did not increase fecal PP excretion or decrease hepatic PP concentration. The present data indicate that accumulation of PP is not amenable to stimulation of fecal fat excretion.     

Effect of coix on plasma, liver, and fecal lipid components in the rat fed on lard- or soybean oil-cholesterol diet

To determine the influence of dietary coix on lipid metabolism, the effect of coix on plasma, liver, and fecal lipid components was studied using Sprague-Dawley male rats. All rats were divided into four groups, and the rats of each group were fed the coix-lard diet, coix-soybean oil diet, or the respective control diets (containing 1% cholesterol each) for 27 days. Plasma and liver cholesterol levels in the coix-lard diet group significantly decreased as compared with those in the control group, whereas there was no effect on the fecal excretion of cholesterol. The decreases in the concentrated liver triglyceride and the increases in the fecal excretion of triglyceride were found in coix-soybean oil diet group. Moreover, liver and fecal phospholipid levels in both coix diet groups significantly increased. But there were no significant changes in plasma and fecal bile acids in either coix diet group. These results suggest the possibilities that coix may have an inhibitory action on cholesterol synthesis in liver, a facilitating effect on biliary excretion of triglyceride, and an acceleratory action on phospholipid synthesis in liver.     

Effects of Arachis hypogaea nutshell extract on lipid metabolic enzymes and obesity parameters

The aim of the present study was to assess the effects of peanut (Arachis hypogaea L.) shell extracts (PSE) on lipases and to evaluate its potential development for the treatment of obesity. The peanut shells were extracted in 95% ethanol, and the extracts were screened for inhibitory effects on pancreatic lipase (PL) and lipoprotein lipase (LPL) activities as well as on lipolysis of 3T3-L1 adipocytes. We also examined in vivo whether PSE could prevent the body weight gain induced by feeding a high-fat diet to male Wistar rats for 12 weeks. PSE inhibits a number of lipases, including PL, LPL and, possibly, hormone sensitive lipase (HSL). PSE-treated Wistar rats showed increased fecal lipid excretion respect to the control group. Body weight and body weight gain, and liver size, were significantly lower in rats fed the high-fat diet with 1% of PSE (w:w diet) than in those fed the high-fat diet alone. The rats treated with PSE showed reduced triacylglycerol content in the liver, as well as the serum glucose and insulin. The inhibitory activity of PSE on the lipid metabolic enzymes and the increase in fecal fat excretion suggests that PSE might be useful as a treatment to reduce the dietary fat absorption. The observed reduction in intracellular lipolytic activity of cultured 3T3-L1 adipocytes may reduce the levels of circulating free fatty acids. The observed effects are likely induced by more than one bioactive component of PSE. The PSE actions may, at least in part, be attributed to the inhibition of fat absorption in the digestive tract and the reduction of the adipocyte lipolysis.     

Effect of probiotics, Bifidobacterium breve and Lactobacillus casei, on bisphenol A exposure in rats

Bisphenol A (BPA), a putative endocrine disruptor, may be taken up by humans via the diet and have adverse effects on human health. In this study, we evaluated whether the probiotics, Bifidobacterium breve strain Yakult (BbY) and Lactobacillus casei strain Shirota (LcS), could exert a protective effect against dietary exposure to BPA. A group of rats fed on a diet containing 5% BbY or 5% LcS showed three advantageous effects compared to the control group; (i) the area under the blood concentration-time curve of BPA after its oral administration was significantly decreased, (ii) the amount of BPA excreted in the feces was significantly greater (2.4 times), and (iii) the percentage of BPA bound to the sediment fraction of the feces was significantly higher. These results suggest that BbY and LcS reduced the intestinal absorption by facilitating the excretion of BPA, and that these probiotics may suppress the adverse effects of BPA on human health.     

Comparison of the Activity of the Tryptophan-NAD Pathway between Rats Fed a Fat-free Diet and a Fat Diet

The effect of dietary fat on tryptophan-NAD metabolism was investigated. Weanling male rats of the Sprague Dawley strain were fed a 40% casein diet (nicotinic acid-free) with or without 20% fat for 13 days. Although the food intake in 13 days was significantly higher in the fat-free group than in the fat group, the gains in body weight in the two groups were almost the same, because of the same energy intakes. The urinary excretion of tryptophan metabolites such as quinolinic acid, niacin and N¹-methylnicotinamide was greatly increased in the fat group in comparison with that in the fat-free group. The urinary excretion of xanthurenic acid was almost the same in the two groups. The blood NAD level of the fat group was significantly increased. The activities of liver amino-carboxymuconate-semialdehyde decarboxylase and liver nicotinamide methyltransferase in the fat group were significantly reduced, and that of liver NMN adenylyltransferase was significantly increased. The changes of these three enzymes could be advantageous for the increased formation of NAD from tryptophan. As a result, the feeding of a high fat diet to rats increased the formation of niacin and niacin-related compounds.     

Effect of wheat bran on excretion of radioactively labeled estradiol-17 beta and estrone-glucuronide injected intravenously in male rats.

Urinary and fecal estrogen excretion were studied in male rats fed a non-fiber wheat starch diet (dietary fiber less than 1%; NF group; n = 4), a low-fiber wheat flour diet (dietary fiber 2%; LF group; n = 4) or a high-fiber wheat bran diet (dietary fiber 11.6%; HF group; n = 3). Short-term effects of the experimental diet on estrogen excretion were studied after i.v. injection of 5 microCi (0.185 MBq) of [14C]estradiol-17 beta (E2) into the tail vein of the rats fed the diets for 2 days. After 3 weeks on the experimental diets, the long-term effects were studied after injection of 5 microCi of [14C]E2 and 10 microCi of [3H]estrone-3-glucuronide (E1-gluc). The diet was found to affect estrogen excretion. The short-term effect indicated that rats fed the HF diet excreted a relatively large amount of labeled compounds in the feces during the first day after injection, while rats fed the NF or the LF diets excreted about half that amount over the same period. On the other hand, urinary excretion of labeled compounds was significantly higher in the NF and LF rats. The long-term effect resulted in steeper slopes (P less than 0.05) of the fecal excretion profiles of rats fed the HF diet as compared with rats fed the NF and LF diets, indicating an accelerated fecal excretion of labeled compounds in the HF rats. The kinetic profiles of 14C and 3H radioactivity in blood plasma indicated a fast decrease (t1/2 of less than 2 min) for both [14C]E2 and [3H]E1-gluc. It was concluded that, owing to the short-term effect of wheat bran intake, during the first 24 h after i.v. administration relatively large amounts of radioactively labeled compounds are excreted in feces of rats fed the HF diet. In contrast, excretion is lower in urine of these rats. When the microflora is adapted to the experimental diet the wheat bran diet still results in an accelerated fecal excretion of labeled compounds, which might be attributed to an interruption of the enterohepatic circulation of estrogens. This might result in lowered plasma and/or tissue estrogen levels and hence a decreased exposure of estrogen-sensitive tissue to estrogens, which might decrease risk on mammary (breast) cancer development.     

Comparison of the effects of di(2-ethylhexyl)phthalate, a peroxisome proliferator, on the vitamin metabolism involved in the energy formation in rats fed with a casein or gluten diet

In order to find an alleviation method for the adverse effect of environmental endocrine disrupters, we studied the effects of the putative endocrine disrupter and peroxisome proliferator, di(2-ethylhexyl)phthalate (DEHP), on animal growth and vitamin metabolism. It is known that the effects of chemical compounds such as xenobiotics differ according to the dietary protein source. We compared the effects of dietary DEHP administration on rats fed with a diet containing milk casein or wheat gluten. The increased conversion ratio of tryptophan to nicotinamide by DEHP administration was significantly higher in the casein group than in the gluten group. We also investigated the effects of DEHP on the urinary excretion of other vitamins. DEHP administration resulted in decreased urinary excretion of vitamin B(1), vitamin B(2), and pantothenic acid.     

Effects of diet on titratable acid-base excretion in grasshoppers

Despite the potential for diet to affect organismal acid-base status, especially in herbivores, little is known about the effects of diet on acid-base loading and excretion. We tested the effects of diet on acid-base loading and excretion in grasshoppers by (a) comparing the fecal acid-base content of 15 grasshopper species collected from the field and (b) comparing fecal acid-base excretion rates of Schistocerca americana grasshoppers fed vegetable diets that differed in their ashed and raw acid-base contents. The field experiments indicated that grass-feeding species excrete fairly neutral fecal pellets, while forb/mixed-feeding species vary widely in their fecal acid-base contents. In the laboratory experiment, acid-base excretion rates were positively correlated with dietary ashed base intake rates but were not correlated with the acid-base content of raw, unashed diet or feeding rate. These experiments suggest that some diets could strongly challenge the acid-base homeostasis of herbivores; in some grasshoppers, dietary acid-base loads could produce certainly lethal 1-unit changes in average body pH within 6 h if they were not excreted.     

Long-term feeding effects of heated and fried oils on hepatic antioxidant enzymes,absorption and excretion of fat in rats

Long-term feeding effect of heated and fried peanut (PNO), rice bran (RBO) and palm oil (PO) in the diet on the hepatic antioxidant enzyme status and absorption and excretion of fats were studied in laboratory rats. The rats were fed oils heated to 180°C continuously for a period of 72 h or laboratory fried at 20% level in the diet for 18 weeks. The results of the study indicated a significant increase in the catalase activity in HO groups and decrease in the FRO groups. The GPx activity while significantly low in HO groups was high in FRO groups, whereas, significant decrease in GST activity was observed in both PNO-HO/FRO groups. Increased activity was noted in RBO-FRO and PO-HO/FRO groups. The SOD activity showed a mixed response in different heated/fried oils and a marginal increase in the levels of fecal fat excretion was observed in some of the heated/fried oil groups. The results indicated no appreciable damage with respect to these antioxidant enzymes. Also, feeding heated fats as high as 20% in the diet for long duration does not result either in reduced food intake or excess fecal fat excretion.     

Effects of lowering food intake by high phosphorus diet on parathyroid hormone actions and kidney mineral concentration in rats

We investigated whether lowering food intake by high phosphorus (P) diet influenced parathyroid hormone (PTH) actions, bone turnover markers, and kidney mineral concentration in rats. Rats in two of the three groups were respectively given free access to a control diet (C group) and a high P diet (HP group) for 21 days. Rats in another group (PF group) were pair-fed the control diet with the HP group. Compared to the C and PF groups, serum PTH concentration, urinary C-terminal telopeptide of type I collagen excretion, and kidney calcium and P concentrations were significantly higher in the HP group. Urinary excretion of cAMP was significantly lower in the HP group than in the C and PF groups. These results suggested that high P diet decreased PTH action in the kidney and increased bone resorption and kidney mineral concentrations independently of lowering food intake.     

Effects of Lowering Food Intake by High Phosphorus Diet on Parathyroid Hormone Actions and Kidney Mineral Concentration in Rats

We investigated whether lowering food intake by high phosphorus (P) diet influenced parathyroid hormone (PTH) actions, bone turnover markers, and kidney mineral concentration in rats. Rats in two of the three groups were respectively given free access to a control diet (C group) and a high P diet (HP group) for 21 days. Rats in another group (PF group) were pair-fed the control diet with the HP group. Compared to the C and PF groups, serum PTH concentration, urinary C-terminal telopeptide of type I collagen excretion, and kidney calcium and P concentrations were significantly higher in the HP group. Urinary excretion of cAMP was significantly lower in the HP group than in the C and PF groups. These results suggested that high P diet decreased PTH action in the kidney and increased bone resorption and kidney mineral concentrations independently of lowering food intake.     

Hypolipidemic and antiperoxidative effect of coconut protein in hypercholesterolemic rats

Effect of coconut protein in rats fed high fat cholesterol containing diet on the metabolism of lipids and lipid peroxides was studied. In addition, effect of coconut protein were compared with rats fed L-arginine. The results indicate that those fed coconut protein and those fed L-arginine showed significantly lower levels of total cholesterol, LDL+ VLDL cholesterol, Triglycerides and Phospholipids in the serum and higher levels of serum HDL cholesterol. The concentration of total cholesterol, triglycerides and phospholipids in the tissues were lower in these groups. There was increased hepatic cholesterogenesis which is evident from the higher rate of incorporation of labeled acetate into free cholesterol. Increased conversion of cholesterol to bile acids and increased fecal excretion of bile acids were observed. Feeding coconut protein results in decreased levels of Malondialdehyde in the heart and increased activity of Superoxide dismutase and Catalase. Supplementation of coconut protein causes increased excretion of urinary nitrate which implies higher rate of conversion of arginine into nitric oxide. In the present study, the arginine supplemented group and the coconut protein fed group produced similar effects. These studies clearly demonstrate that coconut protein is able to reduce hyperlipidemia and peroxidative effect induced by high fat cholesterol containing diet and these effects are mainly mediated by the L-arginine present in it.     

共轭亚油酸对高脂血症大鼠脂质代谢及visfatin基因表达水平的影响

目的建立高脂血症大鼠模型,分析共轭亚油酸（CLA）对其脂质代谢和visfatin基因表达水平的影响,为进一步研究CLA对脂肪代谢的调控机制奠定基础。方法用高脂饲料饲喂雄性Wistar大鼠,4周后断尾采血测定血清甘油三酯（TG）、总胆固醇（CHO）和血糖（GLU）含量,将构建成功的高脂血症大鼠分为实验组和对照组,实验组每天定时灌胃CLA（0.8 mL/0.1 kg）,每周定时称重,记录采食量;4周后眼球采血,测定血清中GLU、CHO、TG、低密度脂蛋白（LDL）、高密度脂蛋白（HDL）水平;断颈处死大鼠,分离体脂并提取肝脏总RNA,半定量RT-PCR分析visfatin基因表达水平。结果高脂饲料饲喂4周后,模型组大鼠血清TG、CHO、GLU明显高于对照组大鼠（P〈0.05）,表明高脂大鼠模型构建成功。灌胃CLA 4周后,实验组大鼠体重、体脂和采食量低于对照组大鼠（P〈0.05）,血清中GLU、CHO、TG、LDL含量明显降低,但实验组HDL浓度升高。RT-PCR实验结果表明,实验组大鼠visfatin基因表达水平明显低于对照组大鼠（P〈0.05）。结论CLA能降低高脂血症大鼠摄食量,改善高血脂大鼠脂质代谢,并能降低visfatin基因的表达水平。     

Effect of dietary inclusion of Lactobacillus acidophilus ATCC 43121 on cholesterol metabolism in rats

This study examined the effects of Lactobacillus acidophilus ATCC 43121 (LAB) on cholesterol metabolism in hypercholesterolemia-induced rats. Four treatment groups of rats (n = 9) were fed experimental diets: normal diet, normal diet+LAB (2 x 10(6) CFU/day), hypercholesterol diet (0.5% cholesterol, w/w), and hypercholesterol diet + LAB. Body weight, feed intake, and feed efficiency did not differ among the four groups. Supplementation with LAB reduced total serum cholesterol (25%) and VLDL + IDL + LDL cholesterol (42%) in hypercholesterol diet groups, although hepatic tissue cholesterol and lipid contents were not changed. In the normal diet group, cholesterol synthesis (HMG-CoA reductase expression), absorption (LDL receptor expression), and excretion via bile acids (cholesterol 7 alpha-hydroxylase expression) were increased by supplementation with LAB, and increased cholesterol absorption and decreased excretion were found in the hypercholesterol diet group. Total fecal acid sterols excretion was increased by supplementation with LAB. With proportional changes in both normal and hypercholesterol diet groups, primary bile acids (cholic and chenodeoxycholic acids) were reduced, and secondary bile acids (deoxycholic and lithocholic acids) were increased. Fecal neutral sterol excretion was not changed by LAB. In this experiment, the increase in insoluble bile acid (lithocholic acid) reduced blood cholesterol level in rats fed hypercholesterol diets supplemented with LAB. Thus, in the rat, L. acidophilus ATCC 43121 is more likely to affect deconjugation and dehydroxylation during cholesterol metabolism than the assimilation of cholesterol into cell membranes.     

The nature of the ingested protein has no effect on lean body mass during energy restriction in overweight rats

Severe energy restriction in obesity not only leads to fat mass loss but also to lean mass loss. The aim of this study was to compare the capacity of casein, a slowly digested protein, and milk soluble proteins (MSP; rapidly digested) to limit the loss of lean mass induced by energy restriction. Obesity was first induced in male Wistar rats by a 5-week feeding with a high-fat high-sucrose diet. The impact of energy restriction was then studied with high-protein (32%) diets containing either casein, MSP, or a 50/50 mixture of both proteins for 3 weeks (n = 10 per group). Food intake, body weight, nitrogen balance, creatinine, and 3-methyl-histidine excretion were measured during energy restriction. Then, tissue weights, plasma metabolic parameters (amino acids, glucose, insulin, cholesterol, triglycerides), and in vivo liver and extensor digitorum longus (EDL) muscle protein synthesis rates were measured in postabsorptive state at the end of the experimental period. Although significant differences relevant to protein metabolism were observed between groups (protein intake, plasma amino acid concentrations, fecal nitrogen excretion, muscle protein synthesis rates), week per week, there were no significant differences in nitrogen balance whatever the protein used. In conclusion, our results show that in young overweight energy restricted rats, using a high-protein diet, the nature of protein intake has no influence on body protein retention.