Ott E A, Kivipelto J
Animal Science Department, University of Florida, Gainesville 32611-0910, USA.
J Anim Sci. 1999 Nov;77(11):3022-30. doi: 10.2527/1999.77113022x.
Thoroughbred and Quarter Horse yearlings (n = 24; 335+/-7 d of age) were used in a 112-d feeding trial to determine whether chromium (Cr) supplementation would alter growth, development, and energy metabolism of growing horses on high-concentrate diets. The horses were assigned at random within breed and gender subgroups to one of four treatment groups: A) basal concentrate; B) basal plus 175 microg of Cr/kg concentrate; C) basal plus 350 microg of Cr/kg concentrate; and D) basal plus 700 microg of Cr/kg concentrate. Chromium was provided via Cr tripicolinate (Prince Agri Products, Quincy, IL). The horses were weighed, measured for withers and hip height, heart girth, and body length and underwent ultrasound evaluation for croup fat thickness. The concentrate was fed for ad libitum consumption for two, 1.5-hr feeding periods daily. Coastal bermudagrass (Cynodon dactylon) hay was group-fed (six animals/group) at 1% of BW daily. Feed intake was 60% concentrate and 40% hay, resulting in a supplemental Cr intake of 0, 105, 210, and 420 microg/kg diet for groups A, B, C, and D, respectively. Colts consumed more concentrate and total feed than did fillies (P < .05), but no dietary effect on feed intake was detected. Colts weighed more than fillies at the completion of the experiment (P = .0754), but no dietary effects on weight, body measurements, or croup fat were detected. An i.v. glucose tolerance test (.2 g of glucose/kg BW) and an i.v. insulin sensitivity test (.1 IU of insulin/kg BW) were conducted on each animal during the third 28-d period of the experiment. Plasma glucose peaked immediately following injection and decreased more rapidly in animals consuming the high-Cr diet than in those consuming the control diet (P < .01). Mean glucose fractional turnover rate values increased (P = .0369) and mean half-life of glucose decreased (P = .0634) in response to the high Cr supplementation. Plasma glucose depletions in animals fed the other two diets were between and not different from (P > .10) the depletions in control animals or in those fed high-Cr diets. No difference in insulin sensitivity was detected (P > .10). Results indicate that Cr tripicolinate supplementation of yearling horses increases the rate at which glucose is metabolized and may lower the plasma glucose concentration. No effect of Cr supplementation on development of the animals was detected.
选用纯种马和夸特马一岁马驹（n = 24；年龄335±7天）进行为期112天的饲养试验，以确定补充铬（Cr）是否会改变高浓缩日粮饲养条件下生长马匹的生长、发育和能量代谢。在品种和性别亚组内，将马匹随机分为四个处理组之一：A）基础浓缩料组；B）基础浓缩料 + 每千克浓缩料添加175微克铬组；C）基础浓缩料 + 每千克浓缩料添加350微克铬组；D）基础浓缩料 + 每千克浓缩料添加700微克铬组。通过吡啶羧酸铬（Prince Agri Products公司，伊利诺伊州昆西）提供铬。对马匹进行称重，测量鬐甲高、臀高、胸围和体长，并通过超声评估臀部脂肪厚度。每天分两个1.5小时的时段自由采食浓缩料。以体重的1%每天给沿海百慕大草（狗牙根）干草进行分组饲喂（每组6只动物）。采食量为60%浓缩料和40%干草，A、B、C、D组日粮中铬的摄入量分别为0、105、210和420微克/千克。公驹比母驹消耗更多的浓缩料和总饲料量（P < 0.05），但未检测到日粮对采食量有影响。在试验结束时，公驹体重比母驹重（P = 0.0754），但未检测到日粮对体重、身体测量指标或臀部脂肪有影响。在试验的第三个28天期间，对每只动物进行静脉注射葡萄糖耐量试验（每千克体重注射0.2克葡萄糖）和静脉注射胰岛素敏感性试验（每千克体重注射0.1国际单位胰岛素）。注射后血浆葡萄糖立即达到峰值，且与对照日粮组相比，采食高铬日粮的动物血浆葡萄糖下降更快（P < 0.01）。由于补充高剂量铬，葡萄糖平均分数周转率值升高（P = 0.0369），葡萄糖平均半衰期缩短（P = 0.0634）。采食其他两种日粮的动物血浆葡萄糖消耗介于对照动物和采食高铬日粮动物之间，且差异不显著（P > 0.10）。未检测到胰岛素敏感性有差异（P > 0.10）。结果表明，给一岁马驹补充吡啶羧酸铬可提高葡萄糖代谢速率，并可能降低血浆葡萄糖浓度。未检测到补充铬对动物发育有影响。
