饲粮添加铜、铁和锌对牛组织和血液铅和镉含量的影响

本研究旨在探讨饲粮添加必需微量元素铜、铁和锌对肉牛组织和血液铅和镉含量的影响。选用 ２０头 １２月龄肉牛，随机分为 ２组，每组 １０头，各组分别饲喂基础精饲料（对照组）和基础精饲料中添加铜 ２０ｍｇ、铁 ２００ｍｇ和锌 ２００ｍｇ的试验精饲料（试验组），粗饲料自由采食。试验期为 １５０ｄ。每天以组为单位计算牛的采食量；每 ３０ｄ称取牛体重并采集血液样品，试验结束后，屠宰试验牛，采集肾脏、肝脏、心脏、胰脏、脾脏、瘤胃、大肠及背肌组织样品，测定血液和组织中铅和镉含量。结果表明：牛精饲料中添加铁、铜和锌后，平均日增重极显著地提高了１２．５０％（Ｐ＜０．０１），料重比极显著地降低了 １５．６８％（Ｐ＜０．０１）；铅含量在胰脏和瘤胃中极显著增加（Ｐ＜０．０１），在脾脏和血液中显著减少（Ｐ＜０．０５），在其余组织中无显著变化（Ｐ＞０．０５），铅蓄积的器官主要是胃；镉含量在肾脏、肝脏、脾脏、瘤胃和大肠中均极显著增加（Ｐ＜０．０１），但心脏中的镉含量极显著降低（Ｐ＜０．０１），镉蓄积的器官主要是肾脏。结果提示，在饲粮中添加铜、铁和锌可以改善肉牛的生长性能，但不能有效减少脏器及肌肉组织中铅和镉的蓄积。

Dietary Supplementation with Copper,Iron and Zinc Affects Contents of Lead andCadmium in Tissues and Blood of Beef Cattles

This experiment was conducted to investigate the effects of dietary supplementation with copper(Cu),iron(Fe) and zinc(Zn) on contents of lead(Pb) and cadmium(Cd) in tissues and blood of beef cattles.Twenty beef cattles aged 12 months were randomly divided into 2 groups with 10 cattles in each group.Cattles were fed a basal concentrate(control group) and the basal concentrate supplemented with 20 mg Cu,200 mg Fe and Zn 200 mg(experimental group),respectively.Roughage was fed ad libitum.The experiment lasted for 150 d.Feed intake of cattles were calculated by group per day;body weight was recorded and blood sample was collected every 30 d,at the end of the experiment,all cattles were slaughtered to collect samples of kidney,liver,heart,pancreas,spleen,rumen,large intestine and dorsal muscles,and the contents of Pb and Zn in tissues and blood were determined.The results showed as follows: supplementation of Cu,Fe and Zn in concentrate significantly increased average daily gain by 12.50%(P<0.01),but significantly decreased feed to gain by 15.68%(P<0.01);there was a significant increase in Pb content in pancreas and rumen(P<0.01),and a significant decrease in that in spleen and blood(P<0.05),but Pb content in other tissues was not changed significantly(P>0.05),and Pb mainly accumulated in the rumen;Cd contents in kidney,liver,spleen,rumen and large intestine were all significantly increased(P<0.01),but Cd content in heart was significantly decreased(P<0.01),and Cd mainly accumulated in the kidney.The results indicate that dietary supplementation with Cu,Fe and Zn can improve growth performance of beef cattles,but can not effectively reduce the accumulation of Pb and Cd in tissues and muscles.