高锌对断乳大鼠生长发育及行为功能的影响

刚断乳Ｗｉｓｔａｒ大鼠１６只分为两组。Ⅰ组喂常锌饲料（３０ｍｇ／ｋｇ），Ⅱ组喂给高锌饲料（１０００ｍｇ／ｋｇ），实验期６周。观察对断乳大鼠生长发育及行为功能的影响。结果表明，喂养后前两周，高锌组（Ⅱ组）动物体重增长及饲料消耗大于常锌组（Ⅰ组），而两周后则相反。脑及海马重量没有差别，但Ⅱ组的脑重指数及海马指数要大于Ⅰ组（Ｐ＜０．０５），胸腺重量Ⅱ组明显小于Ⅰ组（Ｐ＜０．０１），且Ⅱ组中有两只动物脾脏肿大。Ⅱ组血清总蛋白、白蛋白含量明显小于Ⅰ组（Ｐ＜０．０１），且股骨最大负重也显著少于Ⅰ组（Ｐ＜０．０１），而海马及血清中的锌浓度则高于Ⅰ组（Ｐ＜０．０１）。Ⅱ组动物脑中游离牛磺酸含量明显高于Ⅰ组（Ｐ＜０．０５），而逃避实验中的错误次数则明显少于Ⅰ组（Ｐ＜０．０５），但逃避时间显著多于Ⅰ组（Ｐ＜０．０１）。提示锌过高对动物的生长发育及行为功能有不利的影响。

EFFECT OF EXCESSIVE ZINC ON GROWTH,DEVELOPMENT AND BEHAVIOR IN WEANLING RATS

The effect of excessive dietary zinc on growth and behavior in weanling rats were observed.The result indicated that the increment of body weight and amount of consumption of diet in excessive zinc group (group Ⅱ) within two weeks after feeding experimental diet were higher than those in adequate zinc diet at libitum group (group I).The status was contrary beyond two weeks feeding experimental diet.There was no difference of brain and hippocampus weights between two groups.The indices of brain and hippocampus of group Ⅱ were higher than those of group I(P<0.05),and weight of thymus of group Ⅱ was lower than that of group Ⅰ(P<0.01).The zinc contents in hippocampus and serum in group Ⅱ were higher than those in group Ⅰ (P<0.01),and the free taurine content in brain in group Ⅱ was higher than that in group Ⅰ (P<0.05).The fault frequency in escape test in group Ⅱ was lower than that in group Ⅰ (P<0.05),but escape time in group Ⅱ was much more than that in group I(P<0.01).It suggested that excessive dietary zinc could supress the animal growth and damage the behavior function.