Department of Animal and Food Sciences, University of Kentucky, Lexington 40546, USA.
J Anim Sci. 2013 May;91(5):2158-68. doi: 10.2527/jas.2012-5794. Epub 2013 Mar 5.
Selenium plays a role in the antioxidant mechanism via the selenoenzyme glutathione peroxidase (GSH-Px). Change in Se status because of Se depletion or supplementation is associated with a change in GSH-Px activity and could potentially affect antioxidant status. This study evaluated the impact of change in Se status on measures of antioxidant status and oxidative stress in adult horses. Twenty-eight horses were blocked by age and gender and were randomly allocated to 1 of 4 dietary treatment groups: low Se (LS), adequate Se (AS), high organic Se (SP), and high inorganic Se (SS). For 196 d, LS, SP, and SS received a low-Se diet (0.06 mg Se/kg DM) to allow for depletion of Se stores, whereas AS received an adequate Se diet (0.12 mg Se/kg DM). Then, for the next 189 d, LS and AS were maintained on the same diets, whereas SP was supplemented with Se-yeast and SS with sodium selenite to allow for a total dietary Se intake of 0.3 mg Se/kg DM. Blood samples were collected throughout the study. Variables of interest included whole blood Se and GSH-Px activity, serum vitamin E concentration, total antioxidant capacity (TAC), serum malondialdehyde (MDA), and triiodothyronine and thyroxine concentrations. Data were analyzed using ANOVA with repeated measures. Whole blood Se and GSH-Px activity decreased in LS, SP, and SS during the depletion phase and increased in SP and SS with supplementation (treatment × time, P < 0.001). At the conclusion of the supplementation period, GSH-Px activity was greater in SP and SS compared with AS and LS (P < 0.05). Vitamin E status remained adequate throughout the study, and no differences existed between treatments. Serum TAC did not change in response to Se depletion or repletion. Serum MDA was greater for AS than LS during depletion (P < 0.05) but similar across treatments after supplementation. Overall, change in Se status did not have a large impact on TAC or MDA, possibly because the horses maintained an adequate vitamin E status. However, Se supplementation at 0.3 mg/kg DM increased GSH-Px activity above that of the horses fed an adequate diet based on the 2007 NRC recommendations, indicating a potential benefit to feeding greater Se diets to horses kept in low-Se areas.
硒通过硒酶谷胱甘肽过氧化物酶 (GSH-Px) 发挥抗氧化机制中的作用。由于硒缺乏或补充而导致的硒状态变化与 GSH-Px 活性的变化有关，并可能影响抗氧化状态。本研究评估了硒状态变化对成年马抗氧化状态和氧化应激测量指标的影响。28 匹马按年龄和性别分组，并随机分为 4 个饮食处理组之一：低硒 (LS)、适量硒 (AS)、高有机硒 (SP) 和高无机硒 (SS)。196 天内，LS、SP 和 SS 接受低硒饮食 (0.06 mg Se/kg DM)，以耗尽硒储存，而 AS 接受适量硒饮食 (0.12 mg Se/kg DM)。然后，在接下来的 189 天内，LS 和 AS 继续接受相同的饮食，而 SP 用硒酵母补充，SS 用亚硒酸钠补充，以允许总膳食硒摄入量为 0.3 mg Se/kg DM。在整个研究过程中采集血样。感兴趣的变量包括全血硒和 GSH-Px 活性、血清维生素 E 浓度、总抗氧化能力 (TAC)、血清丙二醛 (MDA)、三碘甲状腺原氨酸和甲状腺素浓度。使用具有重复测量的方差分析对数据进行分析。在耗竭阶段，LS、SP 和 SS 中的全血硒和 GSH-Px 活性降低，而 SP 和 SS 中的 GSH-Px 活性在补充阶段增加 (处理×时间，P < 0.001)。在补充期结束时，SP 和 SS 中的 GSH-Px 活性高于 AS 和 LS (P < 0.05)。整个研究过程中维生素 E 状况均充足，且处理之间无差异。血清 TAC 对硒的消耗或补充没有变化。在耗竭期间，AS 的血清 MDA 高于 LS (P < 0.05)，但补充后处理之间相似。总的来说，硒状态的变化对 TAC 或 MDA 没有太大影响，这可能是因为这些马保持了充足的维生素 E 状态。然而，以 0.3 mg/kg DM 的量补充硒可使 GSH-Px 活性高于基于 2007 年 NRC 建议的充足饮食喂养的马，表明在低硒地区饲养马时，喂给富含硒的饮食可能会带来益处。
