Abstract

This study was carried out to observe the effects of dietary sources of vitamin A and Zn levels on Zn and vitamin A distribution in rats fed excess vitamin A diet. In this study, 40 weanling male rats of the Sprague-Dawley strain, weighing 40-50g, were chosen and divided into for groups by dietary Zn levels and the sources of vitamin A. The two levels of dietary Zn were supplied: adequate Zn(30mg Zn/Kg diet), low Zn(3mg Zn/Kg diet). Excess vitamin A level was 100 times of RDA, retional and $\beta$-carotene were used as the sources of vitamin A. Vitamin A concentration of plasma and liver were significantly higher in rats fed retional than in rats fed $\beta$-carotene (p<0.05), but these were not affected by dietary Zn levels. Vitamin A accumulationin the liver appeared to be servere in rats fed retinol and low Zn diet. Zn levels of plasma and liver were not affected by the sources of vitamin A whereas Zn levels of kidney were slightly lower in retinol group, and Zn levels of tests were found to be significantly lower in rats fed retinol and low Zn diet. Fragility of erythrocytes in hypotonic saline soultion was greater in low Zn groups, whereas the lower fragility was found in adequate Zn groups in feeding excess vitamin A diet. Thus, these results suggest that an adequate Zn intake is preferable when excess vitamin A is taken, and $\beta$-carotene intake is more beneficial than retinol in order to diminish toxic effects of vitamin A.

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