Engle T E, Fellner V, Spears J W
Department of Animal Science, Box 7621, North Carolina State University, Raleigh, NC 27695-7621, USA.
J Dairy Sci. 2001 Oct;84(10):2308-13. doi: 10.3168/jds.S0022-0302(01)74678-4.
An experiment was conducted to determine the effects of dietary copper (Cu) on Cu status and lipid metabolism in Holstein cows. Three primiparous and 21 multiparous Holstein cows were utilized in this experiment. Groups of three cows similar in parity, days in milk, and milk yield were assigned randomly to one of the following three treatments: 1) control (no supplemental Cu), 2) 10 mg of Cu/kg of DM from Cu sulfate (CuSO4), and 3) 40 mg of Cu/kg of DM from CuSO4. Liver Cu concentrations were higher in Cu supplemented cows at the end of the 61-d study. Cows receiving 40 mg of Cu/kg of DM had higher liver Cu concentrations than cows receiving 10 mg of Cu. Plasma Cu concentrations were similar across treatments. Total serum cholesterol concentrations were higher in cows receiving supplemental Cu. Cows receiving 40 mg of Cu/kg of DM had higher serum cholesterol concentrations than cows receiving 10 mg of Cu. Dry matter intake, average daily milk production, and milk lipid, protein, and somatic cell numbers were similar across treatments. On d 61, milk fatty acids C18:1 trans and C18-conjugated dienes were lower in cows receiving supplemental Cu relative to the nonsupplemented controls. Cows receiving 40 mg of Cu/kg of DM had higher C12:0 and lower C18:2 and total polyunsaturated fatty acids in milk than cows receiving 10 mg of Cu/kg of DM. These results indicate that Cu supplementation alters lipid metabolism in high producing dairy cows and that Cu supplementation at 40 mg/kg of DM for 61 d can elevate liver Cu concentrations to levels considered to be marginally toxic in dairy cattle.
进行了一项实验，以确定日粮铜（Cu）对荷斯坦奶牛铜状态和脂质代谢的影响。本实验使用了3头初产和21头经产荷斯坦奶牛。将 parity、泌乳天数和产奶量相似的三头奶牛分为一组，随机分配到以下三种处理之一：1）对照（不补充铜），2）来自硫酸铜（CuSO4）的10 mg Cu/kg DM，3）来自硫酸铜（CuSO4）的40 mg Cu/kg DM。在61天研究结束时，补充铜的奶牛肝脏铜浓度较高。接受40 mg Cu/kg DM的奶牛肝脏铜浓度高于接受10 mg Cu的奶牛。各处理间血浆铜浓度相似。补充铜的奶牛总血清胆固醇浓度较高。接受40 mg Cu/kg DM的奶牛血清胆固醇浓度高于接受10 mg Cu的奶牛。各处理间干物质摄入量、平均每日产奶量以及乳脂、蛋白质和体细胞数相似。在第61天，与未补充铜的对照组相比，补充铜的奶牛乳脂肪酸C18:1反式和顺式共轭二烯含量较低。接受40 mg Cu/kg DM的奶牛乳中C12:0含量较高，C18:2和总多不饱和脂肪酸含量低于接受10 mg Cu/kg DM的奶牛。这些结果表明，补充铜会改变高产奶牛的脂质代谢，并且在61天内以40 mg/kg DM的剂量补充铜可将肝脏铜浓度提高到被认为对奶牛有轻微毒性的水平。
