肝脏内乳蛋白前体物代谢规律的研究

The Metabolic Pattern of Milk Protein Precursor in the Liver

选择6只安装门静脉、肝静脉和股动脉慢性血管瘘的健康的泌乳中期萨能奶山羊作为试验动物,采用2×2交叉实验设计,每组3只,试验日粮由精饲料和粗饲料组成,且精饲料和粗饲料比例分别为4∶6(高粗料组)和6∶4(高精料组),研究不同精粗比日粮对泌乳中期奶山羊肝脏氨基酸代谢的影响。结果表明,门静脉血浆中高精料组异亮氨酸、亮氨酸、赖氨酸、蛋氨酸、组氨酸、天冬氨酸、精氨酸、支链氨基酸及总必需氨基酸浓度均高于高粗料组,且异亮氨酸达到显著水平,赖氨酸达到极显著水平,而生糖氨基酸和总氨基酸浓度低于高粗料组,差异不显著;肝静脉血浆中高精料组赖氨酸浓度显著高于高粗料组,丙氨酸、甘氨酸、脯氨酸的浓度显著低于高粗料组,其他氨基酸浓度差异不显著;股动脉血浆中高精料组赖氨酸浓度显著高于高粗料组,其余氨基酸浓度无显著差异,两种日粮对股动脉血浆中支链氨基酸、总必需氨基酸、生糖氨基酸及总氨基酸浓度的影响均不显著。两种日粮对门静脉、肝静脉、股动脉血氨浓度无显著影响;高精料组门静脉、肝静脉、股动脉血浆中的尿素含量显著高于高粗料组;高精料组肝静脉血浆中胰岛素、胰高血糖素、生长激素浓度及胰岛素样生长因子均高于高粗料组,但均达到显著性差异。结论:不同精粗比日粮影响着肝脏内的氨基酸代谢,高精料日粮可显著增加血浆尿素水平,对血浆中相关激素无显著影响。

Six healthy mid--lactating Saanen dairy goats with catheters placed in the portal vein, a branch of the hepatic and femoral artery were used in a randomized crossover trial designed to evaluate the effect of concentrate to forage ratio on amino acid metabolism in liver. Diets content forage and concentrate, the concentrate to forage ratio were 4：6（high forage group, HF） and 6：4（high concentrate group, HC）. The results showed that the portal plasma concentrations of isoleucine, leucine, lysine, methionine, histidine, aspartate, arginine, branched chain amino acid and total essential amino acids were higher, especially isoleucine, lysine, while the concentrations of glucogenic amino acid and total amino acid were lower, but no markedly difference when goats fed HC diet than HF diet; In hepatic vein, the lysine concentration was markedly higher and the concentrations of alanine, glycine, proline were markedly lower when goats fed HC diet than HF diet, and other amino acids were not significantly difference; Except the concentrations of iysine, other amino acids concentration were no markedly change in femoral artery when goats fed HC diet compared with HF diet, and the concentrations of branched chain amino acid, total essential amino acids, glucogenic amino acid and total amino acid were not significantly effects There were no marked effect on plasma NH3 concentration in portal vein, hepatic vein, femoral artery between two treated diets~ The plasma urea concentration in portal vein, hepatic vein, femoral artery were markedly higher in goats fed HC diet than HF diet, The concentration of insulin, glucagon, GH, IGF-1 in hepatic vein plasma were not significantly improved when goats fed HC. Results： The metabolism of amino acids in liver was affected by concentrate to forage ratio, and higher concentrate diet significantly increased the plasma urea concentration, but hormones concentration was not affected .