Arthington J D
Institute of Food and Agricultural Sciences, Range Cattle Research and Education Center, University of Florida, Ona 33865, USA.
J Anim Sci. 2008 Jun;86(6):1472-7. doi: 10.2527/jas.2007-0672. Epub 2008 Feb 13.
Sugarcane molasses is a widely used animal feed by-product, but is concentrated in S (approximately 1%, DM basis) and has been shown to reduce the Cu status of cattle. Dietary S may also antagonize Se; therefore, two 90-d studies were conducted with forage-fed, yearling steers (12 pens; 2 steers/pen for each study) to investigate the impact of molasses supplementation on measures of Se status. In Exp. 1, steers were assigned isonitrogenous supplements with equivalent amounts of TDN from 2 sources (molasses or corn). Supplemental Se was provided (3.0 mg of Se/d; Na selenite) to both treatments. After 90 d of supplementation, steers provided corn diets had greater (P = 0.02) liver Se concentrations and tended (P = 0.07) to have greater ADG compared with steers supplemented with molasses. Irrespective of treatment (P >/= 0.54), plasma Se concentrations decreased (P < 0.001) and plasma glutathione peroxidase activity increased (P < 0.001) from d 0 to 90. In Exp. 2, sources of supplemental Se (2.5 mg/ d), fed within molasses supplements, were compared. Treatments included 1) Na selenite, 2) Se-yeast (Sel-Plex, Alltech, Nicholasville, KY), or 3) no Se (control). Cattle provided supplemental Se, irrespective of source, had greater (P </= 0.01) liver and plasma Se concentrations and greater (P </= 0.01) plasma glutathione peroxidase activity compared with control steers on d 60 and 90. Measures of Se status did not differ among steers supplemented with Na selenite and Se-yeast. These data suggest that dietary S, derived from sugarcane molasses, may antagonize liver tissue accumulation of Se in cattle. The Se status of cattle consuming sugar-cane molasses was similar when provided 2.5 mg of supplemental Se/d from Na selenite or Se-yeast sources.
甘蔗 molasses 是一种广泛使用的动物饲料副产品，但 S 含量较高（约 1%，以干物质计），且已证明会降低牛的铜状态。日粮中的 S 也可能拮抗 Se；因此，进行了两项为期 90 天的研究，以饲喂牧草的一岁公牛（12 个围栏；每项研究每个围栏 2 头公牛）来研究添加 molasses 对 Se 状态指标的影响。在实验 1 中，给公牛分配了来自 2 种来源（molasses 或玉米）的等量 TDN 的等氮补充剂。两种处理均提供补充 Se（3.0 mg Se/d；亚硒酸钠）。补充 90 天后，与补充 molasses 的公牛相比，饲喂玉米日粮的公牛肝脏 Se 浓度更高（P = 0.02），且平均日增重有增加趋势（P = 0.07）。无论处理如何（P >= 0.54），从第 0 天到第 90 天，血浆 Se 浓度降低（P < 0.001），血浆谷胱甘肽过氧化物酶活性增加（P < 0.001）。在实验 2 中，比较了在 molasses 补充剂中饲喂的补充 Se 来源（2.5 mg/d）。处理包括 1）亚硒酸钠，2）硒酵母（Sel-Plex，奥特奇公司，肯塔基州尼古拉斯维尔），或 3）不添加 Se（对照）。在第 60 天和第 90 天，与对照公牛相比，无论 Se 来源如何，补充 Se 的牛肝脏和血浆 Se 浓度更高（P <= 0.01），血浆谷胱甘肽过氧化物酶活性更高（P <= 0.01）。补充亚硒酸钠和硒酵母的公牛之间的 Se 状态指标没有差异。这些数据表明，来自甘蔗 molasses 的日粮 S 可能会拮抗牛肝脏组织中 Se 的积累。当从亚硒酸钠或硒酵母来源每天提供 2.5 mg 补充 Se 时，食用甘蔗 molasses 的牛的 Se 状态相似。
