The site of the interaction between dietary fiber and the small intestine and its nutritional significance in rats fed excessive doses of Food Red No. 2.

为了探讨膳食纤维(DF)对大鼠摄食量、生长速度、食物效率、蛋白质消化率和生物学价值的影响机制(S)，在不同部位切除大鼠的消化道不同部位，观察了膳食纤维对大鼠摄食量、生长速度、食物效率、蛋白质消化率和生物学价值的影响。在体重约100g的大鼠上进行了空肠切除、回肠切除、空回肠切除(保留约10%的小肠)、盲肠切除(带回盲瓣或不带回盲瓣)和回肠直肠吻合术。生长恢复后，饲喂基础日粮(B)、B加5%AM(C)、结果表明：(1)与空肠切除大鼠相比，饲料B中添加5%AM对大鼠的生长发育有较大的抑制作用：空肠是AM毒性的主要发生部位。(2)同时添加5%BDF可完全消除空肠和回肠切除大鼠的AM毒性，表明BDF的有益作用是在肠腔内实现的。AM和BDF的这些作用与日粮蛋白质来源的消化吸收效率是一致的。当剩余的小肠长度至少为50%时，BDF的影响必然会发展。当剩余的小肠长度为全长的10%时，BDF的作用消失。因此，为了发挥BDF的作用，需要一定长度的小肠才能充分地相互作用。(3)我们发现BDF的有益作用是由于降低了食糜的小肠转运速度(SITS)。延迟SITS可促进被Am抑制的营养物质的利用。(4)另外，延迟SITS可能是由于50ppm的盐酸吗啡对Am的毒性有部分保护作用，从而促进了内源性阿片类药物的释放。

The mechanism(s) by which dietary fiber (DF) exerts beneficial effects on food intake, growth rate, food efficiency, and digestibility and biological value of dietary protein in rats fed toxic dosed of Food Red No. 2 (amaranth, Am) were investigated in rats received resection at different sites of digestive tract.Jejunectomy, ileectomy, jejuno-ileal resection (remaining about 10% of the small intestine), cecectomy (with or without ileocecal valve), and ileo-rectostomy were performed in rats weighing about 100 g. After growth recovery, they were fed 3 types of diets: purified basal diet (B), B plus 5% Am (C), and C plus 5% DF (prepared from sugar beet, BDF).The results obtained were as follows:(1) The growth rate of ileectomized rats were more severely depressed by the addition of 5% Am to the diet B compared with that of jejunectomized rats: the results show that the jejunum is the main site of development of Am-toxicity.(2) The concurrent addition of 5% BDF to diet C completely eliminated Am-toxicity in both Jejunectomized and ileectomized rats, showing that beneficial effects of BDF is realized in the lumen of the small intestine. These effects of Am and BDF were compatible with the digestive-absorptive efficiency for dietary protein source. BDF's effects necessarily developed when the remaining small intestinal length was at least 50%. When the remaining small intestine was 10% of the entire length, BDF's effect disappeared. Therefore for the development of BDF's effect, a certain length of the small intestine is required to sufficiently interact each other.(3) We found that beneficial effects of BDF was due to dlaying the small intestinal transit speed (SITS) of the chyme. Delay of SITS enhanced the utilization of nutrients which were inhibited by dietary Am.(4) Moreover, delay of SITS was considered to be caused by enhanced release of endogeneous opioids from small intestinal mucosa, since 50 ppm dietary morphine hydrochloride partially protected Am-toxicity.