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.

膳食纤维（DF）对喂食有毒剂量食品红2号的大鼠的食物摄入量、生长率、食物效率以及膳食蛋白质的消化率和生物学价值产生有益影响的机制（阿马兰斯，Am）的活性，分别在空肠切除、回肠切除、空回肠联合切除的大鼠中进行了研究在重约100 g的大鼠中进行盲肠切除术（保留约10%的小肠）、盲肠切除术（有或没有回盲瓣）和回肠-直肠造口术。生长恢复后，分别饲喂3种类型的饲料：纯净基础饲料（B）、B +5% Am（C）和C +5% DF（由甜菜制成，BDF），结果如下：（1）在B饲料中添加5% Am，对去回肠大鼠的生长速度抑制作用比去空肠大鼠更严重，说明空肠是Am中毒的主要部位。(2)在空肠切除和回肠切除大鼠中，同时向饲料C中添加5% BDF完全消除了Am毒性，表明BDF的有益作用在小肠腔中实现。Am和BDF的这些作用与对日粮蛋白质源的消化吸收效率一致。当小肠剩余长度至少为50%时，BDF的作用必然产生。当小肠剩余长度为全长的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来充分相互作用。(3)我们发现BDF的有益作用是由于降低食糜的小肠通过速度（SITS）。延迟SITS提高了被日粮Am抑制的养分利用率。(4)此外，SITS的延迟被认为是由小肠粘膜内源性阿片类物质的释放增强引起的，因为50 ppm的饮食盐酸吗啡部分保护了Am毒性。

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.