Engle T E, Spears J W, Xi L, Edens F W
Department of Animal Science and Interdepartmental Nutrition Program, North Carolina State University, Raleigh 27695-7621, USA.
J Anim Sci. 2000 Oct;78(10):2737-44. doi: 10.2527/2000.78102737x.
Forty-eight Angus and Hereford x Angus steers were used to determine the effects of copper (Cu) on lipid and catecholamine metabolism. Steers were stratified by weight within breed and randomly assigned to treatments. Treatments consisted of 0 (control, no supplemental Cu), 10, or 40 mg of supplemental Cu (from Cu2(OH)3Cl)/kg DM. Steers were fed a corn silage-soybean meal-based growing diet for 42 d. Animals were then switched to a high-concentrate finishing diet and remained on the same dietary treatments. On d 70, indwelling jugular catheters were nonsurgically inserted into five steers per treatment. Blood samples were obtained from steers after a 24-h period of feed withdrawal, 1 h after feeding, and after i.v. administration of norepinephrine and were subsequently analyzed for nonesterified fatty acid (NEFA) and catecholamine concentrations. Average daily gain over the finishing period was higher (P < 0.06) in steers receiving supplemental Cu. Serum total cholesterol concentrations were reduced (P < 0.05) on d 84 and 112 in steers supplemented with Cu. Serum norepinephrine (P < 0.14) and NEFA concentrations following feed withdrawal tended (P < 0.12) to be higher in Cu-supplemented steers. Postfeeding norepinephrine concentrations tended to be higher (P < 0.14) in Cu-supplemented steers. Nonesterifled fatty acid concentrations were lower (P < 0.10) in Cu-supplemented steers after norepinephrine administration. Backfat depth was decreased (P < 0.10) and longissimus muscle polyunsaturated fatty acid percentages were increased (P < 0.10) in steers receiving supplemental Cu. These results indicate that Cu addition to a finishing diet containing 5 mg Cu/kg DM alters lipid metabolism. The reduction in backfat depth may be due to copper altering catecholamine metabolism in steers.
选用48头安格斯牛以及赫里福德×安格斯杂交阉牛，以确定铜（Cu）对脂质和儿茶酚胺代谢的影响。阉牛按品种内体重分层，并随机分配至各处理组。处理组分别为补充0（对照组，不额外添加铜）、10或40毫克铜（以碱式氯化铜形式）/千克干物质。阉牛先饲喂以玉米青贮料 - 豆粕为主的生长日粮42天。之后改为高能量育肥日粮，并维持相同的日粮处理。在第70天，每个处理组通过非手术方式向5头阉牛插入颈静脉留置导管。在禁食24小时后、采食后1小时以及静脉注射去甲肾上腺素后采集阉牛血样，随后分析非酯化脂肪酸（NEFA）和儿茶酚胺浓度。在育肥期，补充铜的阉牛平均日增重更高（P < 0.06）。在第84天和112天，补充铜的阉牛血清总胆固醇浓度降低（P < 0.05）。补充铜的阉牛在禁食后的血清去甲肾上腺素（P < 0.14）和NEFA浓度有升高趋势（P < 0.12）。采食后，补充铜的阉牛去甲肾上腺素浓度有升高趋势（P < 0.14）。补充铜的阉牛在注射去甲肾上腺素后非酯化脂肪酸浓度较低（P < 0.10）。补充铜的阉牛背膘厚度降低（P < 0.10），背最长肌多不饱和脂肪酸百分比升高（P < 0.10）。这些结果表明，在含5毫克铜/千克干物质的育肥日粮中添加铜会改变脂质代谢。背膘厚度的降低可能是由于铜改变了阉牛的儿茶酚胺代谢。
