Effects of phytate feeding and Zn deficiency on phytase activities of intestinal mucosa.

植酸盐可降低大鼠肠黏膜植酸酶活性。这可能与膳食中植酸对锌在肠道中的吸收有抑制作用有关。因此，本试验研究了植酸盐饲喂和锌缺乏对肠道植酸酶活性的影响。30只生长雄性大鼠分别饲喂含植酸饲料（1%或2%）和缺锌饲料（锌含量为3 μ g / kg）。因此，在饲养3周后，含植酸饮食和缺锌饮食均显著降低了大鼠股骨中的锌含量。取小肠上部（1/3）制备粘膜匀浆，测定酶活性。在本试验中，植酸饲料降低了粘膜植酸酶活性，而锌缺乏则没有。对照组饲粮黏膜匀浆锌含量为0.241 μ g / mg蛋白质，含植酸和缺锌饲粮黏膜匀浆锌含量为0.214 ~ 0.286 μ g / mg蛋白质。各组肠黏膜锌含量无明显差异。同时测定了同一粘膜匀浆的碱性磷酸酶活性，即锌酶活性。试验饲粮之间无显著差异。由此可见，植酸饲喂导致肠道植酸酶活性下降，并非锌缺乏所致，而是受矿物质吸收抑制剂植酸的影响。

The lowering of phytase activities of intestinal mucosa is observed when phytate is fed to rats. This may be caused by inhibitory effect of dietary phytate to zinc absorption in intestinal tract. Therefore, effects of phytate feeding and zinc deficiency on intestinal phytase activity was studied.Phytate containing diets (1% or 2%) or zinc deficient diets (zinc : 3 mu g / kg of diet) were fed to the thirty growing male rats. Thus, zinc contents of femur of rats were significantly decreased by both phytate-containing and zinc deficient diets after three weeks of feeding. Mucosal homogenate were prepared from the upper part (1/3) of small intestine for measurement of enzyme activities.In this experiments, mucosal phytase activity was decreased by phytate-feeding, but not by zinc deficiency. Zinc contents of mucosal homogenate were 0.241 mu g / mg protein for the control diet, and 0.214-0.286 mu g / mg protein for phytate-containing and zinc deficient diets. There was not obvious different in the amount of zinc in intestinal mucosa. Alkaline phosphatase activities, which known as zinc enzyme, were also measured for same mucosal homogenate. There was no significant difference among the experimental diets. Therefore, it is clear that the decreased intestinal phytase activities by phytate feeding is not caused by zinc deficiency which effected by phytate, inhibitor for mineral absorption.