饲料钙水平对大鼠血钙及钙调蛋白的影响

为研究饲料中钙与血钙（Ｃａ）及钙调蛋白（ＣａＭ）的关系，本实验通过在大鼠低钙饲料中补充不同量的钙，平行研究饲料内钙水平对血钙及ＣａＭ的影响。Ｗｉｓｔａｒ大鼠按体重和性别分层均匀分为７组。基础低钙（ＬＣ）饲料是以玉米面为主的膳食配方配制，其中低钙特别突出。ＬＣ组大鼠血清钙水平明显低下，仅及常规饮食（ｓｔｏｃｋ）组的一半，体重增长迟缓，下丘脑ＣａＭ活性明显低下；当饲料补Ｃａ后，血Ｃａ水平随补Ｃａ量逐渐升高，补Ｃａ可使ＣａＭ水平升高，体重也随之升高，呈明显的量效关系，ＬＣ＋６００ｍｇ／ｋｇＣａ组血Ｃａ接近正常水平。说明饲料低钙、低血Ｃａ和细胞内ＣａＭ三者的变化是紧密联系的。当饲料内总钙在１０００ｍｇ／ｋｇ时，即ＬＣ＋６００ｍｇ／ｋｇ组，上述生长迟缓的状态即得到改善，Ｐ＜０．０１。

Effect of Dietary Calcium on Serum Calcium and Calmodulin Activity of Brain and Hypothalamus in rats

The effect of low calcium (LC)diet supplemented with various amount of calcium on serum calcium and calmodulin of rats was studied. The LC diet was mainly composed of corn low in calcium. The calcium content of LC diet was only half of that of the stock diet. Seventy Wistar rats were divided into 7 groups by weight and sex. Results showed that serum calcium in LC group was low and calmodulin activity was also low. These parameters were improved while calcium was supplemented in LC diet. There is a significant dose response relationship among diet calcium, serum calcium and growth. When the total calcium in diet was increased up to 1000mg/kg, serum calcium level was closed to that of normal and higher than the serum calcium in LC group significantly. The study demonstrated that low dietary calcium, hypocalcemia and low calmodulin are associated. When total dietary calcium was up to 1000mg/kg, the growth retardation was attenuated.