Sprague-Dawley rats were fed diets containing 7.5% dietary fiber as cellulose (control), pectin, psyllium or oat bran with or without 0.3% added cholesterol for 3 wk. Among rats fed cholesterol, liver total lipid and cholesterol concentrations were significantly lower in groups fed pectin, psyllium and oat bran compared with cellulose-fed controls. Cholesterol feeding resulted in significantly greater liver cholesterol in rats fed cellulose, psyllium and oat bran but not in those fed pectin. Among rats fed cholesterol, total serum cholesterol levels were significantly lower in those fed pectin than in those fed psyllium, oat bran or cellulose. When cholesterol was fed, the oat bran-fed group had significantly higher butyrate and the pectin-fed group had significantly higher propionate concentrations in the hepatic portal vein than did cellulose-fed controls. The groups fed psyllium, oat bran and pectin all had significantly higher fecal neutral sterols than did the cellulose-fed group when cholesterol was fed. Without dietary cholesterol only pectin-fed rats had significantly higher fecal excretion of neutral sterols than those fed cellulose. Dietary fiber did not influence fecal acidic sterol excretion. However, the addition of cholesterol to these fiber diets was accompanied by a significantly higher bile acid excretion than that of animals fed cellulose without cholesterol. The results of this study indicate that soluble dietary fibers may exert their hypocholesterolemic effect by increasing excretion of fecal neutral sterols.

Ninety-six male Sprague-Dawley rats were randomly assigned to eight dietary treatments. Rats were fed, with ad libitum access, diets containing 10% dietary fiber as cellulose (control), pectin, psyllium or oat bran with or without 0.3% added cholesterol for 3 wk. Among cholesterol-fed rats, liver total cholesterol was significantly lower in rats fed diets supplemented with either pectin or psyllium compared with those fed cellulose. In contrast, rats fed oat bran with cholesterol had significantly higher liver cholesterol concentrations compared with cellulose-fed animals. Liver total lipid concentrations were significantly lower in groups fed pectin and psyllium with or without dietary cholesterol compared with cellulose-fed controls. Pectin feeding with or without dietary cholesterol significantly lowered plasma total cholesterol compared with cellulose feeding. Oat bran had no effect on plasma total cholesterol compared with control diets. Hepatic sterol synthesis was significantly greater for animals fed soluble dietary fibers compared with those fed cellulose, but the effect on intestinal sterol synthesis was less pronounced.

Day-old chicks were fed control or manganese (Mn deficient diets ad libitum for 25 d. The chicks subsequently were refed control diet for up to 5 d. Mn deficiency significantly decreased growth rate and feed intake compared to controls. After 25 d of depletion, bone Mn concentration was 2% that of controls and 88% of the deficient chicks exhibited signs of perosis. Sulfate (35SO4) uptake into uronic acid was significantly depressed in cartilage from the Mn-depleted chicks and increased rapidly with refeeding, which may indicate increased glycosaminoglycan (GAG) biosynthesis or increased sulfation of the GAG molecule. In vitro activity of glycosyltransferases suggest that GAG synthesis may be interrupted by Mn deficiency. Somatomedin activity, serum insulin and glucose levels were not influenced significantly by Mn deficiency. Thus, while Mn deficiency decreased growth and GAG synthesis these effects were not mediated by somatomedin.

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