Effects of viscous indigestible polysaccharides on the pancreas exocrine function were investigated in growing rats. Rats were fed a nonfiber diet or a diet containing approximately 5% of one of the following fibers: apple pectin, lambda-carrageenan, locust bean gum, gum xanthan, guar gum or sodium (Na) alginate. Pancreatic-bile secretion was found to be elevated in rats fed for 2 wk the highly viscous polysaccharides, sodium alginate, locust bean gum, gum xanthan and guar gum. The polysaccharides may have interfered with the digestion and absorption of nutrients, resulting in a decreased digestibility and an enlargement of digestive organs. When alginic acid and calcium alginate, insoluble polysaccharides that did not contribute to viscosity, were given to rats, they had no effect on pancreatic and biliary secretion compared with sodium alginate. The results demonstrate that consumption of viscous indigestible polysaccharides leads to changes in the exocrine pancreatic-biliary function and may depress the process of digestion and absorption. Rats may compensate for the inefficiency of digestion and absorption with a hyperplasia/hypertrophy of digestive organs and an increased secretion of digestive juice.

SummaryThis investigation was attempted in order to further clarify the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on lipid metabolism in rats. Ninety-three percent ethyl eicosapentaenoate (EPAconc) and 91% ethyl-docosahexaenoate (DHAconc) were used and supplied at the 3% level to a hypercholestero lemic basal diet which contained 5% lard. Four experimental diets were prepared from (1) 5% olive oil, (2) 2% olive oil +3% ethyl-linoleate, (3) 2% olive oil +3% EPAconc, and (4) 2% olive oil +3% DHAconc plus hypercholesterolemic basal diet. Young male rats were fed on these diets for respective periods of 10 and 20 days. Concentrations of serum lipids in rats fed on the diets (2), (3) and (4) were compared to those of the control group (diet (1)). Serum total cholesterol level was significantly lower only in the animals fed on DHAconc, whereas serum triglyceride concentration was significantly lower only in the animals fed on EPAconc. Serum phospholipid level was significantly lowered both in the animals fed on either EPAconc or DHAconc. Serum lipid peroxide concentration was elevated in these two groups of animals, while serum alpha-tocopherol concentration was lower in both groups of animals fed on EPAconc and DHAconc, respectively, although these findings were less marked in the rats on the EPAconc diet.From these findings, it is postulated that EPA and DHA have different effects on lipid metabolism in rats with hypercholesterolemia experimentaly induced. Present address;

The effects of three forms of alginate (free acid, sodium and calcium salts) on ingestion and excretion of cholesterol in the rat were studied. For two weeks, Male Sprague-Dawley rats were fed a cholesterolrich diet containing 3 % alginate from the brown alga Ascophyllum nodosum. The food efficiency of the three types of alginate was: Na-alginate > Ca-alginate > alginic acid. A significant increase in the weight of cecum was also observed in alginate diets. Alginate was not effective in preventing the elevation of serum total cholesterol levels, although irregularly changing patterns were observed. The cholesterol level of liver showed a tendency to decrease with alginate feeding, while fecal excretion of cholesterol increased.

The influence of dietary lipids on the liver microsomal mixed function oxidase system and on pentobarbital-induced sleeping time was studied in rats. Giving diets containing (g/kg) 150 olive oil, 150 lard or 150 soya-bean oil for 21 d (Expt 1) increased the cytochrome P-450 content in the order : olive oil < lard < soya-bean oil. When diets containing (g/kg) 150 lard, 150 soya-bean oil, 150 sardine oil or an equal mixture of 50 of each oil were given for 15 d (Expt 2), the cytochrome P-450 content and aminopyrine N-demethylase activity were significantly higher in the sardine-oil and mixed-oil groups than in the lard group, and the activity of aminopyrine N-demethylase was also significantly higher in the soyabean oil group compared with the lard group. A significantly higher activity of NADPH-cytochrome c reductase (EC 1 . 6 . 2 . 5 ) was observed in the sardine-oil group than in the other three groups. Aniline hydroxylase activity and cytochrome b, content remained unchanged in all the groups. Pentobarbitalinduced sleeping time measured on day 15 (Expt 2) varied inversely with the changes in cytochrome P-450 content and aminopyrine N-demethylase activity in the three single-fat groups, but not in the mixedoil group, reflecting liver microsomal metabolic activity for pentobarbital in vivo. From these results, it appears that high intakes of polyunsaturated fatty acids (18: 2n-6, 18: 3n-3, 20:5n-3 and 22: 6n-3) stimulate the liver microsomal mixed function oxidase system.

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