CECAL FERMENTATIONS IN RATS FED OLIGOSACCHARIDES (INULIN) ARE MODULATED BY DIETARY CALCIUM LEVEL
CECAL FERMENTATIONS IN RATS FED OLIGOSACCHARIDES (INULIN) ARE MODULATED BY DIETARY CALCIUM LEVEL
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DOI：
10.1152/ajpgi.1993.264.5.g855
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发表时间：
1993-05-01
影响因子：
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通讯作者：
DEMIGNE, C
中科院分区：
文献类型：
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作者：
REMESY, C;LEVRAT, MA;DEMIGNE, C
在四组喂食不同半纯化饮食的大鼠中，研究了钙对大肠中膳食低聚糖发酵的影响：1) 无纤维，3 g Ca/kg，2) 无纤维，8 g Ca/kg； 3)15%菊粉，3g Ca/kg；或4) 15%菊粉，8g Ca/kg。饲喂无纤维饮食的大鼠的盲肠发酵非常低，并且不受饮食钙水平的影响。喂食菊粉饮食的老鼠盲肠扩大，并进行酸性发酵，丙酸含量相对丰富。在该饮食组中，适应 3 g Ca/kg 水平的大鼠具有非常酸性的发酵和降低的挥发性脂肪酸浓度以及乳酸（L 和 D 异构体）的积累。菊粉饮食导致隐窝柱高度和盲肠粘膜鸟氨酸脱羧酶活性升高，特别是在 3 g Ca/kg 饮食组中。喂食高钙饮食的大鼠盲肠中存在大量不溶性钙和磷（i）的积累。饲喂菊粉可提高可溶性 Ca 和 P(i) 的百分比；在喂食菊粉的大鼠中，盲肠对钙的吸收也明显较高，并且受到膳食钙水平的影响。喂食菊粉饮食的大鼠中可溶性胆汁酸的浓度降低，从而增强了胆汁酸的粪便排泄。这些影响几乎不会因膳食钙水平的变化而改变。在体外，CaP(i) 似乎能有效降低胆汁盐的溶解度，主要是在酸性条件下。总之，大肠中有一个控制管腔 pH 值的系统，其中涉及不溶性 Ca 和 P(i) 的存在。目前的研究结果表明，膳食钙对结肠上皮的保护作用不仅涉及不溶性钙盐（主要是磷酸盐）与胆汁酸的结合，还涉及管腔 pH 值本身的控制和挥发性脂肪酸的产生。
The influence of Ca on the fermentation of dietary oligosaccharides in the large intestine has been investigated in four groups of rats fed different semipurified diets: 1) fiber free, 3 g Ca/kg, 2) fiber free, 8 g Ca/kg; 3) 15% inulin, 3 g Ca/kg; or 4) 15% inulin, 8 g Ca/kg. The cecal fermentations were very low in rats fed the fiber-free diets and were not affected by the dietary Ca level. Rats fed the inulin diets had enlarged cecum with acidic fermentations, relatively rich in propionic acid. In this diet group rats adapted to the 3 g Ca/kg level had very acidic fermentations and depressed volatile fatty acid concentrations together with an accumulation of lactic acid (L and D isomers). Inulin diets brought about a rise in the crypt column height and in the activity of ornithine decarboxylase in cecal mucosa, especially in the 3 g Ca/kg diet group. There was considerable accumulation of insoluble Ca and P(i) in the cecum of rats fed high-Ca diets. Inulin feeding increased the percentage of soluble Ca and P(i); Ca absorption from the cecum was also markedly higher in rats fed inulin and was influenced by the dietary Ca level. The concentrations of soluble bile acids were depressed in rats fed inulin diets, which enhanced the fecal excretion of bile acids. These effects were poorly altered by changes in the dietary Ca level. In vitro it appears that CaP(i) is effective in decreasing the solubility of bile salts, chiefly in acidic conditions. In conclusion there is in the large intestine a system of control of luminal pH, which involves the presence of insoluble Ca and P(i). The present findings suggest that the protective effects of dietary Ca on colonic epithelium involve not only bile acids binding by insoluble Ca salts (mainly phosphate) but also the control of luminal pH itself and of the production of volatile fatty acids.