Sun Jian-Yi, Jing Ming-Yan, Wang Jian-Feng, Zi Nai-Tao, Fu Liang-Jian, Lu Ming-Qi, Pan Lin
The Key Laboratory of Molecular Animal Nutrition, Ministry of Education and Institute of Feed Science, Zhejiang University, Hangzhou, China.
Nutrition. 2006 Feb;22(2):187-96. doi: 10.1016/j.nut.2005.07.007. Epub 2006 Jan 18.
The present study simultaneously investigated the effects of different zinc (Zn) levels on the growth performance and relative biochemical parameters in growing rats and analyzed the molecular mechanism of zinc influencing food intake.
Three diets with different Zn levels--Zn adequate (ZA; 35.94 mg/kg, control), Zn deficient (ZD; 3.15 mg/kg), and Zn overdose (ZO; 347.50 mg/kg)--were fed to rats for 6 wk. Dietary Zn was supplemented with ZnSO4. The relation between zinc and food intake was studied by pituitary cDNA microarrays.
Compared with ZA group, rats fed the ZD diet showed decreases in body weight (P < 0.01), food intake (P < 0.05), tissue zinc concentrations (P < 0.01), and specific activities of alkaline phosphatase (P < 0.01) and copper/Zn superoxide dismutase (P < 0.05), whereas the ZO diet had positive effects on body weight (P < 0.05), zinc concentrations (P < 0.01), and alkaline phosphatase activity (P < 0.05). The villi of the jejunum became shorter (P < 0.01), shriveled, and flattened. This change in morphology decreased absorption surface area, and there was a substantial decrease (P < 0.01) in villi number per unit area in ZD rats. Metallothionein concentration was increased in livers of rats fed ZD (P < 0.01) and ZO (P < 0.05) diets. Moreover, ZD and ZO influenced normal growth and development of organs. The results from pituitary cDNA arrays indicated that different Zn levels affect gene expression of appetite-related peptides, including neuropeptide-Y, melanin-concentrating hormone, ghrelin, calcitonin gene-related product, and serotonin.
The present results showed that zinc deficiency has a negative effect on the growth performance and biochemical parameters of rats. The ZO diet increased body weight (P < 0.05) but had no effect (P > 0.05) on food intake, copper/Zn superoxide dismutase activity, and intestinal morphology. The ZD diet decreased rat food intake by regulating appetite-related gene expression in the pituitary gland.
本研究同时探究了不同锌（Zn）水平对生长大鼠生长性能和相关生化参数的影响，并分析了锌影响食物摄入量的分子机制。
用三种不同锌水平的日粮——锌充足（ZA；35.94毫克/千克，对照）、锌缺乏（ZD；3.15毫克/千克）和锌过量（ZO；347.50毫克/千克）——喂养大鼠6周。日粮中的锌通过硫酸锌补充。通过垂体cDNA微阵列研究锌与食物摄入量之间的关系。
与ZA组相比，喂食ZD日粮的大鼠体重（P<0.01）、食物摄入量（P<0.05）、组织锌浓度（P<0.01）、碱性磷酸酶比活性（P<0.01）和铜/锌超氧化物歧化酶（P<0.05）均降低，而ZO日粮对体重（P<0.05）、锌浓度（P<0.01）和碱性磷酸酶活性（P<0.05）有积极影响。空肠绒毛变短（P<0.01）、萎缩并变平。这种形态变化减少了吸收表面积，ZD大鼠每单位面积的绒毛数量大幅减少（P<0.01）。喂食ZD（P<0.01）和ZO（P<0.05）日粮的大鼠肝脏中金属硫蛋白浓度升高。此外，ZD和ZO影响器官的正常生长和发育。垂体cDNA阵列的结果表明，不同的锌水平会影响与食欲相关肽的基因表达，包括神经肽Y、促黑素细胞激素、胃饥饿素、降钙素基因相关肽和5-羟色胺。
目前的结果表明，锌缺乏对大鼠的生长性能和生化参数有负面影响。ZO日粮增加了体重（P<0.05），但对食物摄入量、铜/锌超氧化物歧化酶活性和肠道形态没有影响（P>0.05）。ZD日粮通过调节垂体中与食欲相关的基因表达来降低大鼠的食物摄入量。
