Effects of Altered Dietary Zinc Intake on Some Growth and Hematological Parameters in Rats

Abstract

The current work was carried out to study the effect of zinc deficient and zinc overdose on some blood parameters, growth hormone bioassay and its bioaccumulation in various body organs. Therefore, 36 weaned female Albino rats was induced divided randomly into 3groups: Zinc deficient (ZD) and overdose (ZO) as well as zinc adequate group as control (ZA) (12/group) by feeding them a diet containing 0.7, 7500 and 35mg Zn/kg respectively, for 8 weeks. The results showed highly significant differences in RBC count, Hb content, HCT%, MCV and MCHC ZA group as compared with ZD and ZO, while WBC count in both ZD and ZO were significantly higher as compared with ZA.Growth hormone level in ZA was significantly higher as compared with both ZD and ZO.ZA, ZO and ZD rats exhibited highest, moderate and lowest daily food intake, respectively. The highest weekly body weight gain was observed in ZA rats as compared with ZO and ZD rats. The ZA showed highly significantly higher relative organs weight to body weight in thymus, ovary, uterus, liver and spleen as compared to ZD and ZO groups. On the other hand, ZO showed significantly higher relative brain and kidney to body weights as compared with ZA. However, no significant relative heart and lung to body weight was observed between ZA, ZD and ZO groups. The mode of Zn bioaccumulation varied organs and treatment dose. Thus, ZD rats showed reduced Zn levels in bone, liver, uterus, skin, spleen, brain, heart and lung as compared with ZA rats. On the other hand, ZO group showed significantly higher Zn level in bone, liver, kidney, skin uterus and lung as compared with ZA group.  From the results, it can be concluded that, zinc deficient and zinc overdose induced a negative effect on RBC count, HCT%, Hb, MCV, MCH, and MCHC.  Zinc deficiency and overdose induced a negative effect on serum growth hormone level, food intake, body weight gain, food efficiency ratio, body length and various body organs weight. Zinc overdose induced accumulation in bone, liver, kidney, uterus, skin and lung. The zinc deficiency produced a drop of zinc content in most organs examined such as bone, liver, heart, uterus, spleen, lung, brain and skin.