甲基供体促仔猪生长的内分泌机制的探讨

试验将 72头始重为 1 0kg左右的杜长嘉仔猪随机分为 3组 ,以添加和不添加蛋氨酸为对照 ,试验组喂以添加 80 0mg/kg的甜菜碱。 3组的基础饲粮组成及营养水平相同 ,试验期为 3 6天。结果表明 ,与不添加蛋氨酸组相比 ,添加甜菜碱组猪的日增重和采食量分别提高了 1 1 .82 %(P <0 .0 5)和 8.71 %(P <0 .0 5) ,饲料转化率提高了 2 .79%(P <0 .0 5) ;与添加蛋氨酸组相比无显著差异 (P >0 .0 5)。此外 ,甜菜碱组肝脏中甜菜碱高半胱氨酸甲基转移酶 (BHMT)活较不添加蛋氨酸组高 61 .4 1 %(P <0 .0 5) ,较添加蛋氨酸组高 55.3 6%(P <0 .0 5) ,血样分析结果显示 ,添加甜菜碱组猪比不添加蛋氨酸组显著降低了血清尿素氮含量 (P <0 .0 1 )。提高了血清总铁结合力、GH和IGF -1水平 (P <0 .0 5)。但与添加蛋氨酸组相比 ,差异均不显著 (P >0 .0 5)。上述结果提示 ,甲基供体一方面通过肝脏BHMT酶的调控下为机体甲基化合成代谢提供甲基 ,发挥节约蛋氨酸的效应 ;另一方面通过增强机体GH和IGF -1的分泌 ,促进生长。

Effect of Methyl-donor on the Performance and the Mechanism of Growth Promoting Hormone in Piglets

Seventy-two piglets were allotted to three groups by weight. Every group included three replicates of eight each. The groups received the same basal diet supplemented with 0,800mg/kg betaine and 2000mg/kg methionine for 36d. The results indicated that betainegroup obviously increased ADG by 11.82%(P<0.05), FI by 8.71%(P<0.05) and BHMT activity in liver by 61.41%(P<0.05), decreased F/G by 2.79%(P<0.05) compared with Metunadded group. Compared with Met-added group, betaine group promoted BHMT activity by 55.36%(p<0.05). In addition, betaine group apparently reduced SUN level by 35.70%(P<0.01) and increased total iron binding ability and GH and IGF-1 levels(P<0.05) in serum respectively compared with Met-unadded group. These results suggested that betaine might exert the following functions:(1)sparing methionine by providing effective labile methyl for methylation products synthesis instead of methionine under control of BHMT.(2)promoting growth by increasing GH and IGF-1 levels in serum.