Effects of Zinc Deficiency On Body Composition of Rats in Different Growth Stages

Abstract

Rats of three different ages, i.e., 4 weeks old (stage 1) , 5 weeks old (stage 2) , and 7 weeks old (stage 3) were assigned to four groups, as follows : initiation, zinc-deficiency, ad libitum control and pair-fed control with 8 rats in each group. Before and 4 weeks after the initiation of feeding trials in each growth stage, animals were sacrificed and plasma zinc concentration and body composition were measured. In the earlier 2 stages, contents of protein, fat and ash were less in the zinc-deficient animals than the pair-fed control. And the ratio of fat/protein was lower in the zinc-deficient animals than the pair-fed ones. It is suggested that zinc deficiency more severely impaired the deposition of fat than that of protein of in the younger rats. On the other hand, these impairments disappeared in the last stage when fat deposition most rapidly occurred in ad libitum groups. It appeared that the suppressive effects of feeding the zinc-deficient diet were attenuated in the latter growth stage.