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

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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.