不同精粗比日粮对泌乳奶山羊肝脏氨基酸代谢和产奶性能的影响

The effect of diets of concentrate to forage ratio on amino acid metabolism in liver and lactation performance of dairy goat

选择6只安装门静脉﹑肝静脉和股动脉慢性血管瘘的健康泌乳中期西农萨能奶山羊作为试验动物,采用2×2交叉试验设计,每组3只,试验日粮由精饲料和粗饲料组成,且精、粗饲料比例分别为4∶6(高粗料组,HF)和6∶4(高精料组,HC),研究不同精粗比日粮对泌乳中期奶山羊肝脏氨基酸代谢及乳产量、乳成分的影响。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(branched chain amino acid,BCAA)及总必需氨基酸(total essential amino acids,TEAA)浓度均高于高粗料组,且赖氨酸达到极显著水平(P<0.01),而生糖氨基酸(glucogenic amino acid,GAA)和总氨基酸(total amino acid,TAA)浓度低于高粗料组,差异不显著(P>0.05)。肝静脉血浆中高精料组赖氨酸浓度显著高于高粗料组(P<0.05),丙氨酸、甘氨酸、脯氨酸的浓度显著低于高粗料组(P<0.05),其他氨基酸浓度差异不显著(P>0.05)。股动脉血浆中高精料组赖氨酸浓度显著高于高粗料组(P<0.05),其余氨基酸浓度无显著差异(P>0.05),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(P>0.05)。两种日粮对门静脉﹑肝静脉﹑股动脉血氨浓度无显著影响(P>0.05);高精料组门静脉﹑肝静脉﹑股动脉血浆中的尿素浓度显著高于高粗料组(P<0.05);高精料组的日产奶量、乳糖含量高于高粗料组,且乳糖含量差异达到显著水平(P<0.05),乳蛋白率和乳脂率均低于高粗料组,差异不显著(P>0.05)。结论:不同精粗比日粮影响着肝脏内的氨基酸代谢,高精料日粮可显著提高血浆尿素水平。

Six healthy mid-lactating Xinong 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 me- tabolism in liver and the lactation performance. 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 vein plasma concentrations of isoleucine, leucine, lysine, methionine, histidine, aspartate, arginine, branched chain amino acid （ BCAA ） and total essential amino acids （ TEAA ） were higher, especially those of lysine（ P〈0.01 ） ,while the concentrations of gLueogenie amino acid （GAA）and total amino acid（TAA） were lower, but with no marked difference （P〉0.05）when goats were fed HC dLet than when goats were fed HF diet. In hepatic vein, the lysine concentration was markedly higher（ P〈0.05 ） and the concentrations of alanine, glyeine, proline were markedly lower（ P〈0.05 ） when goats were fed HC diet than when goats were fed HF diet, and other amino acids were not significantly different（ P〉0.05 ）. Except the concentrations of lysine, other amino acids concentration were no markedly （：hanged（ P〉0.05 ）in femoral artery when goats were fed HC diet compared with when goats were fed HF diet, and the concentrations of branched chain amino acid, total essential amino acids, glucogenic amino acid and total amino acid showed no significant effects（P〉0.05）. There were no marked（P〉0.05 ）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（P〈0.05 ）in goats fed HC diet than in goats fed HF diet; Compared with HF diet, milk production and lactose content were higher（P〈0.05）, and milk protein and milk fat concentration were lower（P〉0.05）in goats fed HC diet. Results：The metabolism of amino acids in liver was affected by concentrate to forage ratio, and higher concentrate diet increased significantly the plasma urea concentration.