吸附剂和营养元素对肉牛体内铅、镉排泄的影响

为了探讨吸附剂蒙脱石及营养元素铜、锌、铁、硒对肉牛体内铅、镉是否具有促排作用,试验选择40头杂交牛随机分为富硒组、微量元素组、蒙脱石组、对照组,每组10头,试验期为150 d,在试验期内每隔1个月收集1次肉牛尿液、粪便测定铅、镉含量;饲养试验结束后屠宰,采集各组织样品测定铅、镉含量。结果表明:肉牛尿液铅、镉排泄量没有明显增加;在8月份,各组粪镉含量均高于对照组(P<0.05或P<0.01);在9—11月份,与对照组相比,各组粪镉含量均无显著差异(P>0.05);在8,11月份,各组粪铅含量均无显著差异(P>0.05);在9,10月份,富硒组和微量元素组粪铅含量均低于对照组,蒙脱石组粪铅含量与对照组相比无显著差异(P>0.05)。说明在饲料中适量补充吸附剂蒙脱石,短期内对肉牛体内铅、镉有明显的促排作用;而补充营养元素铜、锌、铁、硒后,短期内在肉牛体内对镉有促排作用,对铅无促排作用,长期给予不能有效降低肉牛体内铅、镉的蓄积。提示应合理使用饲料添加剂。

Effect of the absorbent and nutrient elements on the excretion of lead and cadmium in beef cattle

To investigate the effect of the montmorillonite sorbent and nutritional elements including copper,zinc,iron and selenium on lead and cadmium excretion in beef cattle,forty heads of hybrid cattle were randomly divided 4 groups of 10 animals each,including the selenium-rich group,the trace-element group,the montmorillonite group and the control group.The experiment lasted for 150 d,and the urine and faeces were collected to determine the contents of lead and cadmium once a month.At the end of the feeding trial,all the beef cattle were slaughtered.The samples of cattle tissues were collected to determine the contents of lead and cadmium.The results showed that after the excretion amounts of the lead and cadmium in the urine did not increase significantly.During August,the contents of cadmium in feces in each experimental group were higher than that of in the control group(P<0.05 or P<0.01).From September to November,there was no significant difference(P>0.05) in the contents of cadmium in feces in each experimental group compared to the control group.During August and November,there was no significant difference(P>0.05) in the contents of lead in feces in each group.During September and October,the contents of lead in feces between the selenium-rich group and the trace-element group were lower than that of in the control group,and there was no significant difference in the contents of lead in feces in the montmorillonite group compared with the control group(P>0.05).The results indicate that the supplement of montmorillonite in the feed has an effect in promoting the excretion of lead and cadmium in a short time.The supplements of copper,zinc,iron and selenium in the feed have an effect in promoting the excretion of cadmium in a short time,but had no effect in promoting the excretion of lead.However,they could not effectively reduce the accumulation of lead and cadmium in tissues of cattle for a long time.It is concluded that the feed additives should be used reasonably.