不同膳食纤维饮食下大鼠粪便矿物元素的测定及其吸收特点

矿物元素是动物体的组成部分，对维持机体正常生理有着重要作用，矿物元素的吸收代谢与膳食纤维密切相关，为研究不同结构的膳食纤维对钾、钠、钙、镁吸收的影响，本文采用原子吸收光谱法对大鼠（Rattus norregius）粪便中的4种矿物元素进行检测，比较2种预处理方法对矿物元素的提取效果，以及7种膳食纤维对4种矿物元素肠道吸收的影响。结果表明，干法灰化-混酸消解更适合提取钙、镁元素，而酸法浸提适合提取钾、钠元素；膳食纤维对钙、镁元素吸收率的影响大于钾、钠元素，总体钙、镁吸收率显著低于钾、钠的吸收率；在钾的吸收率上，纤维素组和麦麸组显著高于木聚糖组、果胶组、菊粉组和魔芋组；在钠的吸收率上，纤维素组和果胶组显著低于其他各组；对于钙的吸收率，木聚糖组和魔芋组显著低于纤维素组和麦麸组；镁吸收率果胶组和魔芋组最低，麦麸组最高，差异具有显著性。不同膳食纤维对矿质代谢有不同的影响，与麦麸相比，木聚糖和魔芋降低钙的吸收，果胶降低钾、钠、镁的吸收，纤维素和麦麸对矿物元素吸收率总体大于其余膳食纤维。

Determination of Mineral Elements in Rat Feces and Its Absorption Characteristics under Different Dietary Fiber Diets

Mineral elements are important components of the animal body and play an important role in maintaining the normal physiology of the body. The absorption and metabolism of mineral elements are closely related to dietary fibers. In order to study the effect of dietary fibers with different structures on the absorption of four mineral elements,atomic absorption spectrometry was used to detect potassium,sodium,calcium and magnesium in rat (Rattus norregius) feces in this article. The extraction effects of two pretreatment methods on mineral elements were compared,and the effects of seven dietary fibers on intestinal absorption of four elements were compared. The results showed that dry ashing method was more suitable for the extraction of calcium and magnesium elements,while dilute acid extraction was suitable for the extraction of potassium and sodium elements. The effect of dietary fiber on the absorption rate of calcium and magnesium was greater than that of potassium and sodium,and the overall absorption rate of calcium and magnesium was significantly lower than that of potassium and sodium. The potassium absorption rate of cellulose group and wheat bran group was significantly higher than that of xylan,pectin,inulin and konjac,while the sodium absorption rate of cellulose and pectin group was significantly lower than that of other groups. For calcium absorption rate,xylan and konjac were significantly lower than cellulose and wheat bran group. The magnesium absorption rate was the lowest in pectin and konjac group,and highest in wheat bran group. The difference was significant. The conclusion is that different dietary fibers have different effects on mineral metabolism. Compared with wheat bran group,xylan and konjac reduce the absorption of calcium. Pectin reduces the absorption of potassium,sodium,and magnesium. While the absorption rate of cellulose and wheat bran to mineral elements is generally greater than that of other dietary fibers.