Spears J W, Harvey R W
Dept. of Anim. Sci., North Carolina State University, Raleigh 27695-7621.
J Anim Sci. 1987 Sep;65(3):830-40. doi: 10.2527/jas1987.653830x.
Thirty Angus steers averaging 357 kg were used to: 1) determine the effect of feeding lasalocid (33 mg/kg diet) on mineral metabolism and 2) determine the effects of varying dietary sodium (Na) and potassium (K) on finishing steers fed lasalocid. Treatments consisted of: 1) control (.25% Na, .5% K); 2) lasalocid (.05% Na, .5% K); 3) lasalocid (.25% Na, .5% K); 4) lasalocid (.05% Na, 1.4% K) and 5) lasalocid (.25% Na, 1.4% K). Ruminal fluid and blood samples were collected on d 28 and 90 of the 102-d study. Gain and feed conversion tended to be higher for steers fed lasalocid with the exception of the .05% Na, 1.4% K treatment. Control steers had lower (P less than .05) erythrocyte K concentrations, reduced (P less than .05) soluble concentrations of magnesium and copper in ruminal fluid and decreased plasma concentrations of zinc (P less than .05) and phosphorus (P less than .10) at 90 d compared with steers fed lasalocid and similar concentrations of Na (.25%) and K (.5%). Increasing dietary Na from .05 to .25% in the presence of lasalocid increased (P less than (P less than .05) molar proportion of ruminal acetate at 28 and 90 d reduced (P less than .05) propionate at 90 d. Increasing K from .5 to 1.4% decreased (P less than .01) soluble Na and increased (P less than .01) soluble K concentrations in ruminal fluid. Steers fed lasalocid (.25% Na, .5% K) had lower concentrations of K (P less than .10) and zinc (P less than .10) in liver than control steers. Sodium and K level also affected tissue concentrations of certain minerals. Results suggest that dietary Na and K influence mineral metabolism and that dietary Na affects ruminal molar proportion of acetate in cattle fed lasalocid.
选用30头平均体重357千克的安格斯阉牛来：1）确定饲喂拉沙洛西（每千克日粮33毫克）对矿物质代谢的影响，以及2）确定不同日粮钠（Na）和钾（K）水平对饲喂拉沙洛西的育肥牛的影响。处理方式包括：1）对照组（0.25% Na，0.5% K）；2）拉沙洛西组（0.05% Na，0.5% K）；3）拉沙洛西组（0.25% Na，0.5% K）；4）拉沙洛西组（0.05% Na，1.4% K）和5）拉沙洛西组（0.25% Na，1.4% K）。在为期102天的研究中，于第28天和第90天采集瘤胃液和血液样本。除了0.05% Na、1.4% K处理组外，饲喂拉沙洛西的阉牛增重和饲料转化率往往更高。与饲喂拉沙洛西且钠（0.25%）和钾（0.5%）浓度相似的阉牛相比，对照组阉牛在第90天时红细胞钾浓度较低（P<0.05），瘤胃液中镁和铜的可溶性浓度降低（P<0.05），血浆锌浓度（P<0.05）和磷浓度（P<0.10）降低。在拉沙洛西存在的情况下，将日粮钠从0.05%提高到0.25%，在第28天和第90天时瘤胃乙酸的摩尔比例增加（P<0.05），在第90天时丙酸减少（P<0.05）。将钾从0.5%提高到1.4%，瘤胃液中可溶性钠减少（P<0.01），可溶性钾增加（P<0.01）。饲喂拉沙洛西（0.25% Na，0.5% K）的阉牛肝脏中的钾（P<0.10）和锌（P<0.10）浓度低于对照组阉牛。钠和钾水平也影响某些矿物质的组织浓度。结果表明，日粮中的钠和钾会影响矿物质代谢，并且日粮中的钠会影响饲喂拉沙洛西的牛的瘤胃乙酸摩尔比例。
