高剂量锌促进猪生长的机理探讨

APPROACH OF THE MECHANISM OF GROWTH PROMOTING EFFECT OF PHARMACOLOGICAL LEVEL OF ZINC IN PIGS

选用 4 2头“杜长大”三元杂交猪 ,分为 2组 (每组 3个重复 ) ,分别饲以添加 10 0mg/kg和30 0 0mg/kg锌 (氧化锌 )的相同饲粮 ,进行了为期 30d的饲养试验 ,然后屠宰取样 ,研究高剂量锌促进猪生长的作用机理。结果显示 :饲粮中添加 30 0 0mg/kg锌显著提高了日增重 (P <0 0 1)和采食量 (P <0 0 1) ;饲料干物质、粗蛋白的消化率明显上升 (P <0 0 1) ;肝脏组织中金属硫蛋白含量增加 (P <0 0 1) ,铜 ,锌 超氧化物歧化酶活力增强 (P <0 0 1) ;肝脏RNA含量和RNA/DNA值显著上升 (P <0 0 1) ;血清胰岛素、胰岛素样生长因子I水平明显升高 (P <0 0 1)。试验结果提示 ,高剂量锌似通过有效清除体内自由基的不良影响 ,增强DNA转录RNA ,促进胰岛素、胰岛素样生长因子I的合成和分泌 ,加强合成代谢 。

Forty two crossbred pigs (Duroc×Landrace×Yorkshire) were used to study the mechanism of growth promoting effect of pharmacological level of zinc.The results showed that with the supplementation of 3000mg/kg zinc from ZnO,ADG and ADFI of pigs,apparent digestibility of DM,CP of the diet was increased siginificantly(P<0.01);concentration of MT and activity of Cu,Zn SOD,content of RNA and RNA/DNA ratio of liver were also enhanced significantly(P<0.01), the levels of insulin and IGF I in serum were elevated obviously (P<0.01).The results obtained from this research implicate that supplement with pharmacological level of zinc promotes growth of pigs by eliminating the unfavorable effect of oxygen radical in the body,accelerating DNA transcripts to RNA to facilitate protein synthesis,and that supplemental zinc stimulate the synthesis and secretion of insulin and IGF 1,so that assimilation is enhanced.