White C L
Institute for Nutritional Physiology, Technical University of Munich, Freising-Weihenstephan, West Germany.
Biol Trace Elem Res. 1988 Sep-Dec;17:175-87. doi: 10.1007/BF02795455.
Body composition and the levels of some plasma metabolites were measured in zinc deficient and control rats with the aim of assessing the nature of the metabolic defects resulting from zinc deficiency. Two experiments, lasting 15 and 20 d, were carried out using 52 immature rats. Zinc deficient animals were fed a diet of 1-2 mg Zn/kg. Pair fed and ad libitum control rats received the same diet with 100 ppm zinc added to the drinking water. Feed intake and growth rate were measured, and the carcasses were analyzed for protein, fat, and ash. In each experiment, a group of rats were killed on d 1 to provide pretreatment values and to allow for estimates of net deposition of carcass components. Lactate, urea, and zinc were assayed in plasma, as well as zinc concentration in carcasses and liver. The main effect of zinc deficiency was to reduce feed intake and efficiency of feed conversion, resulting in a reduced proportion of carcass fat. However, when adjustments were made for difference in body wt because of the reduced feed efficiency, zinc deficiency per se resulted in an increase in the proportion of fat in the carcass. Plasma lactate concentration was unchanged, but urea concentration increased in both pair fed and zinc deficient rats relative to ad libitum fed control animals. The results indicate that a defect in protein synthesis and an increase in energy expenditure, perhaps resulting from increased protein turnover, underlies the reduced growth and efficiency of feed conversion of zinc deficiency.
为了评估锌缺乏导致的代谢缺陷的本质，对缺锌大鼠和对照大鼠的身体组成及一些血浆代谢物水平进行了测量。使用52只未成熟大鼠进行了两个实验，分别持续15天和20天。缺锌动物喂食含锌量为1 - 2毫克/千克的饲料。配对喂食和自由采食的对照大鼠接受相同的饲料，并在饮用水中添加100 ppm的锌。测量了采食量和生长速率，并对胴体进行了蛋白质、脂肪和灰分分析。在每个实验中，一组大鼠在第1天被处死以提供预处理值，并用于估计胴体成分的净沉积量。测定了血浆中的乳酸、尿素和锌，以及胴体和肝脏中的锌浓度。锌缺乏的主要影响是降低采食量和饲料转化效率，导致胴体脂肪比例降低。然而，由于饲料效率降低对体重差异进行调整后，锌缺乏本身导致胴体脂肪比例增加。相对于自由采食的对照动物，配对喂食和缺锌大鼠的血浆乳酸浓度未变，但尿素浓度增加。结果表明，蛋白质合成缺陷和能量消耗增加，可能是由于蛋白质周转增加所致，是锌缺乏导致生长和饲料转化效率降低的基础。
