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The * Wistar Institute of Anatomy and Biology, Philadelphia, PA 19104
Department of Nutrition and Food Science, Drexel University, Philadelphia, PA 19104
The effects of the four major components of dietary fibercellulose, hemicellulose, pectin and ligninon lipid metabolism were studied in meal-fed Wistar rats maintained on a cholesterol-free semipurified diet for 21 days. Transit time was decreased and fecal weight increased compared to rats fed a fiber-free diet. Rats fed cellulose or lignin gained significantly less weight than rats fed hemicellulose or pectin. The fibers had no effect on serum cholesterol levels, but serum triacylgycerol levels were significantly higher in rats fed cellulose. Liver cholesterol levels were higher in cellulose-fed rats but liver triacylglycerol levels were highest in rats fed hemicellulose or pectin. Hepatic cholesterol 7
-hydroxylase and HMG-CoA reductase activities were highest in rats fed cellulose and pectin, respectively. Epididymal fat cell size was similar in all groups but fat cell number was highest in pectin-fed rats. Perirenal fat cell size was greatest in rats fed cellulose or lignin and fat cell number in rats fed cellulose or hemicellulose Lipoprotein lipase activity (per 106 cells) was elevated in epididymal fat of rats fed pectin and in perirenal fat of rats fed hemicellulose. Carcass lipid accumulation was highest in rats fed cellulose or lignin. Rats fed cellulose accumulated significantly higher levels of carcass cholesterol and triacylglycerol. Of the fibers fed, cellulose led to an accumulation of serum, liver and carcass lipid. The four fibers fed represent purified and altered forms of cellular components and the observed effects cannot be extrapolated to diets containing foods rich in one or another of these components.
KEY WORDS: adipose tissue cell size adipose tissue cell number carcass lipid cholesterol 7
-hydroxylase dietary fiber HMG-CoA reductase lipoprotein lipase liver lipids serum lipids
1 Presented at the Meeting of the Federated American Societies for Experimental Biology, 1981. Fed. Proc 40:853, 1981.
2 This work was supported, in part, by grants HL-03299 and AM-27760 and a Research Career Award (HL-00734) from the National Institutes of Health and by grants-in-aid from the National Dairy Council and the Commonwealth of Pennsylvania.
3 Present address: Dept. of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824.
4 Present address: University of Minnesota, The Hormel Institute, Austin, MN 55912.
5 To whom all correspondence should be addressed.
Manuscript received 21 April 1983.