奶牛不同生理阶段血清微量元素含量和氧化状态

选择3～4月龄犊牛、后备母牛和成年母牛(产奶后期、产前及产后1月内).测定了血清Se、Cu、Zn、Mn、Fe含量厦谷胱甘肤过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量.结果表明,除Zn含量外,所测元素含量犊牛明显低于后备母牛和成年牛(P<0.05或P<0.01),后备母牛和成年牛之闻差异不显著(P>0.05),血清Se含量在产奶后期和产前明显下降(P<0.05),血清Cu、Mn含量在产后1月内有降低的趋势,但与产前相比均差异不显著(P>0.05);所测血清氧化状态指标与年龄无明显关系,在妊娠末期和泌乳早期发生改变,血清CAT、GSH-Px、SOD活性和MDA含量在产前和产后1月内最高.表明犊牛上述所测指标最低,奶牛产前和泌乳早期血清微量元素含量和氧化状态失衡.

Serum concentrations of trace elements and oxidative status at different physiological stages of dairy cows

Calves(3-4 month old),replacement heifers,late-lactation cows,cows during one month before and after calving were selected to determine serum concentrations of selenium,zinc,iron,copper and manganese in dairy cows.The following parameters of the oxidative status were also measured in serum:glutathione peroxidase(GSHPx)activity,superoxide dismutase(SoD)activity,catalase(CAT)activity and malondialdehyde(MDA)content.Compared with replacement heifers and mature cows,the lowest serum concentrations of trace elements in calves were detecfed except zinc content(P<0.05 or P<0.01).There were no significant differences for serum concentrations of traceelements among replacement heifers and mature cows(P>0.05).A significant decrease in the of serum concentration of selenium was observed at late-lactation COWS and cows during one month before calving.Although serum concentrations of copper and manganese tended to be decreased in cows during one month after calving,there was no difference compared with cows during one month before calving(P>0.05).Oxidative status of serum in dairy cows was not related to age.Our results confirmed the characteristic metabolic changes associated with late pregnancy and early lactation.Activities of GSH-Px,SOD,CAT and MDA level in serum were the highest around calving.Results suggest that the concentrations of trace elements and oxicative status of serum in calves were the lowest,indicating an imblance in those parameters during one month before calving and early lactation.