여러가지 종류의 사료 섬유질을 섭취하는 쥐의 수분 및 Na 대사에 관한 연구 = Studies on the Water and Na Metabolism of Rats Fed Various Sources of Dietary Fiber

다국어 초록 (Multilingual Abstract)

The effects of several sources of dietary fiber on the water and sodium (Na) metabolism of rats were investigated. Wheat bran (D2), pure cellulose (D3), and ground rice straw (D4) replaced corn in the control diet (D1) at the level of 10%: pectin (DS), which is water-soluble, replaced corn at 5% level. In the growth trial with 45 female weanling rats (Sprague Dawley strain), the growth rate of DS was significantly (P≤.05) lower than those of D1 and D2. No difference in growth rate was found among D3, D4 and D5. With regard to water intake of growing rats, there was no difference among all treatments. In metabolism trial with 30 adult male rats, the dry matter (DM) digestibilities of D3 and D4 were significantly lower than those of D1, D2 and D5. Similar DM digestibilities were found in D1, D2 and D5. As in the case of growing rats, no difference was found in water intake among five treatments. With regard to water holding capacity (WHC) of feces, D3 and D4 showed significantly larger values than D2. The WHC of D1 and D5 were even lower (P≤.05) than D2. The bulls density (BD) of feces was exactly in the inverse relationship with WHC. The BD of D3 and D4 were significantly smaller than the other treatments. D1 and D5 showed significantly larger BD than did D2. In terms of Na excretion routes of urine and feces, D1 and DS excreted significantly more Na via urine than did D3 and D4. The D2 showed intermediate values in this respect. No difference was found in Na^+ and osmotic concentrations either in plasma or urine among dietary treatments. With regard to plasma clearances, there was no difference among all treatments in C_(Na)^+, C_(osm) anti C_(H₂O), The C_(H₂O) values from all treatments showed negative values, indicating that the rats were removing excess solutes in body fluids via urine. Among the water-insoluble fibers, wheat bran appeared to be less fibrous than pure cellulose or ground rice straw in several respects, i.e., growth rate, feral WHC and BD, and the route of Na excretion. Except that it inhibits the growth rate of young rats, pectin brought about the same effect as did the control diet, indicating that the gut microflora fermented the water-soluble pectin. Different nutritional and physiological effects might be expected from rats fed dietary fibers having different solubility in water.