Effects of soluble corn bran arabinoxylans on cecal digestion, lipid metabolism, and mineral balance (Ca, Mg) in rats

• Published in: The Journal of nutritional biochemistry Vol. 10; no. 9; pp. 500 - 509
• Main Authors: Lopez, Hubert W., Levrat, Marie-Anne, Guy, Christine, Messager, Arnaud, Demigné, Christian, Rémésy, Christian
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-09-1999; Elsevier Science; Elsevier
• Subjects: Biological and medical sciences; calcium; cecum; cholesterol; Feeding. Feeding behavior; fermentation; fiber; Fundamental and applied biological sciences. Psychology; Life Sciences; magnesium; Vertebrates: anatomy and physiology, studies on body, several organs or systems; cholesterol; fermentation; magnesium; fiber; calcium; cecum; Cereal bran; Calcium; Rat; Digestive system; Cecum; Gut; Rodentia; Corn; Lipids; Soluble form; Metabolism; Inorganic element; Feeding; Vertebrata; Mammalia; Diet; Animal; Plant origin; Anaerobic fermentation; Magnesium; Dietary fiber
• ISSN: 0955-2863; 1873-4847
• DOI: 10.1016/S0955-2863(99)00036-4

The effects of soluble corn bran arabinoxylans on cecal digestion, lipid metabolism, and mineral utilization [calcium (Ca) and magnesium (Mg)] were investigated in rats adapted to semipurified diets. The diets provided either 710 g/kg wheat starch alone (control) or 610 g/kg wheat starch plus 100 g/kg corn soluble fiber (arabinoxylans) and either 0 or 2 g/kg cholesterol (control + cholesterol and arabinoxylans + cholesterol, respectively). Compared with rats fed the control diets, rats fed the arabinoxylan diets had significant cecal hypertrophy (+50% after 3 days of the fiber adaptation) and an accumulation of short-chain fatty acids, especially propionic acid (up to 45% in molar percentage). Arabinoxylans enhanced the cecal absorption of Ca and Mg (from 0.07 to 0.19 μmol/min for Ca and from 0.05 to 0.23 μmol/min for Mg). Mg balance was enhanced by arabinoxylans (+25%). The arabinoxylan diet markedly reduced the cholesterol absorption from 50% of ingested cholesterol in controls up to approximately 15% in rats adapted to the arabinoxylans diet. Arabinoxylans were effective in lowering plasma cholesterol (approximately −20%). There was practically no effect of the diets on cholesterol in
d > 1.040 lipoproteins (high density lipoproteins) whereas arabinoxylans were very effective in depressing cholesterol in
d < 1.040 lipoproteins (especially in triglyceride-rich lipoproteins). Corn fermentable fiber decreased the accumulation of cholesterol in the liver. In parallel, the arabinoxylan diet counteracted the downregulation of 3-hydroxy-3-methylglutaryl-CoA by cholesterol. These data suggest that arabinoxylans may have a great impact on intestinal fermentation, mineral utilization, and cholesterol metabolism.