The effect of 6'-galactooligosaccharides on bone mineralization of rats adapted to different levels of dietary calcium.
6'-galactooligosaccharides (6'-GOS), a mixture of galactosyl oligosaccharides formed from lactose by the transgalactosyl reaction with beta-D-galactosidase derived from Aspergillus oryzae and Streptococcus thermophillus, are unhydrolyzed in the small intestine and are fermented by the intestinal bacteria. The effects of 6'-GOS on calcium (Ca) absorption and bone mineralization were examined in male Wistar rats adapted to different levels of dietary Ca for 30 days. Dietary 6'-GOS (5 g/100 g of diet) were more potent than control in stimulating Ca absorption in rats fed the Normal-Ca diet (0.5 g of Ca/100 g of diet) after 8-10 days and 18-20 days, and the bone (femur and tibia) Ca content of rats fed the Normal-Ca diet with 6'-GOS were significantly higher than those of the control animals. However, in rats fed the Low-Ca diet (0.05 g of Ca/100 g of diet), 6'-GOS feeding did not affect both the absorption of Ca and the bone mineralization. Ca content in the liquid phase of the cecal digesta was significantly elevated by 6'-GOS feeding in the rats fed the Normal-Ca diet, however, this was unchanged in the rats fed the Low-Ca diet. We conclude that the effect of 6'-GOS on the bone mineralization is affected by dietary Ca concentration used in the experiment, and the stimulatory effect of 6'-GOS on Ca absorption may be partly associated with increased solubility of Ca in the intestinal digesta.
Yakult Central Institute for Microbiological Research, Tokyo, Japan.
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Chonan
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Watanuki
D000042:Absorption; D000222:Adaptation, Physiological; D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects*; D002118:Calcium / Q000008:administration & dosage* / Q000378:metabolism*; D002432:Cecum / Q000378:metabolism; D004032:Diet; D004063:Digestion; D005232:Fatty Acids, Volatile / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008297:Male; D009844:Oligosaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D005232:Fatty Acids, Volatile; D009844:Oligosaccharides; D002118:Calcium