PDF(Pubmed)
Abstract：
This study\'s objective was to determine the effects of increasing the dietary added zinc (Zn) on the milk production, milk somatic cell count (SCC), and immunoglobulin and antioxidant marker concentrations in the blood of dairy cows. Twelve Holstein cows (67 ± 2.5 days in milk) were assigned randomly to (1) a diet containing Zn-methionine at 76 mg/kg of DM (CTL) or (2) CTL top-dressed with about 21 mg/kg of DM extra Zn-methionine (+Zn) for 70 d. The concentrations of reduced (GSH) and oxidized (GSSG) glutathione, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and immunoglobulins in the blood were measured on d 0, 35, and 70. Compared to CTL, +Zn decreased the dry matter intake (DMI) throughout the trial and the milk yield (MY) during the first phase of feeding (0-35 d). It, however, increased the milk yield during the last phase (36-70 d). The +Zn tended to have lower and greater milk protein yields than CTL during the first and last feeding phases, respectively. The +Zn tended to decrease the SCC and was associated with lower plasma GSH: GSSG and lower serum SOD concentrations relative to CTL. The +Zn did not affect the immunoglobulins, MDA, or CAT. Despite the early DMI and MY reduction, the prolonged Zn-methionine supplementation at about 100 mg/kg of DM improved the milk yield, possibly as a result of the improved udder health of dairy cows.
摘要：
本研究的目的是确定增加膳食添加锌（Zn）对牛奶生产的影响，牛奶体细胞计数（SCC），以及奶牛血液中的免疫球蛋白和抗氧化剂标志物浓度。12头荷斯坦奶牛（牛奶中67±2.5天）被随机分配到（1）含有76mg/kgDM（CTL）的锌-蛋氨酸的饮食或（2）CTL顶部覆盖约21mg/kgDM额外的锌-蛋氨酸（Zn）70天。还原（GSH）和氧化（GSSG）谷胱甘肽的浓度，丙二醛（MDA），过氧化氢酶(CAT),超氧化物歧化酶（SOD），在d0、35和70时测量血液中的免疫球蛋白。与CTL相比,在整个试验过程中，Zn降低了干物质摄入量（DMI），并在喂养的第一阶段（0-35d）降低了产奶量（MY）。It,然而,在最后阶段(36-70d)增加了产奶量。在第一个和最后一个饲喂阶段，+Zn倾向于具有比CTL更低和更高的乳蛋白产量。分别。相对于CTL，Zn倾向于降低SCC，并与较低的血浆GSH：GSSG和较低的血清SOD浓度有关。+锌不影响免疫球蛋白，MDA,或CAT。尽管早期的MDI和我的减少，在约100mg/kgDM的时间内补充锌蛋氨酸可提高产奶量，可能是由于奶牛乳房健康状况的改善。
