蛋氨酸羟基异丙酯对犊牛生长、血清生化指标和激素水平的影响

Effects of 2-hydroxy-4-(methylthio) butanoic acid isopropyl ester supplementation on productive performance,serum biochemical indexes and serum hormone levels in dairy calves

本试验旨在通过在犊牛日粮精料补充料中添加蛋氨酸羟基异丙酯（ HMBi）,研究其对犊牛生长、血清生化指标以及激素水平的影响。选择3.5月龄、体质量相近的雪龙黑牛与徐州黄牛杂交肉犊牛12头,进行配对,随机分为对照组和试验组,每组6头,在相同的条件下饲养。对照组在精料补充料中不添加 HMBi,试验组每头犊牛分别在精料补充料中添加4 g/d的 HMBi。试验期间,记录犊牛每天的采食量和粪便形态。试验期1 d、28 d、49 d早晨空腹称量每头牛的体质量,测量体高、体长、胸围和管围等体尺指标。试验期开始和结束前颈静脉采血测定血液指标和激素水平。结果显示,与对照组相比,试验组犊牛的体质量变化不显著（P〉0.05）；在第1~7 d时的粗料采食量显著高于对照组（P〈0.05）；腹泻率极显著低于对照组（P〈0.01）；第28 d的胸深显著高于对照组（P〈0.05）。血清生化指标方面,试验组血清甘油三酯（TG）显著降低（P〈0.05）；血清尿素氮（BUN）在试验后较试验前显著降低（P〈0.05）。血液激素方面,试验组犊牛血清胰岛素（INS）、瘦素（LEP）以及生长激素（GH）、类胰岛素生长因子1（IGF-1）水平与对照组相比,差异不显著（P〉0.05）。表明,在日粮精料补充料中添加4 g/d 的 HMBi能降低犊牛腹泻率,促进胸深发育,促进机体脂肪和蛋白沉积,但对血液激素水平影响不显著。

Twelve hybrid calves derived from snow dragon black cattle and Xuzhou cattle （ average age 4. 5 month） were selected and randomly divided into control group and treatment group with 6 head each. Control group was fed on basal diet while treatment group was fed on bas-al diet supplemented with 4 g/d 2-hydroxy- 4-（ methyl-thio） butanoic acid isopropyl ester（ HMBi） per head. Fe-cal morphology and feed intake were recorded everyday during the experiment and body weight, body height, body length, heart girth, circumference of cannon bone and other body sizes were recorded on day 1, day 28 and day 49 of the experi-ment. Blood samples were collected at the beginning and the end of the experiment. Compared with control group, the body weight had no significant change （P〉0. 05）, the roughage feed intake were significantly incerased at day 1 to day 7 （P〈0. 05）, the diarrhea rates declined （P〈0. 05）, and the chest depth was significantly higher at day 28 （P〈0. 05）. In terms of serum biochemical indexes, the concentration of serum triglyceride was significant lower than that of control group （ P〈0. 05）, and the concentration of BUN was lowered after the experiment （P〈0. 05）. HMBi supplementation did not cast significant effects on the levels of serum insulin, leptin, growth hormone and insulin-like growth factor 1 （P〈0. 05）. HMBi supplementation in dairy calves are capable of improving chest depth, decreasing diarrhea rates and promoting the deposi-tion of fat and protein.