Study on the changes of amino acid profiles rumen degradation for 2 forage grasses at different growth stages in Yellow River | 黄河滩区2种禾本科牧草不同生育期氨基酸瘤胃降解特性研究

Chinese. 研究多年生黑麦草和紫羊茅不同生育期氨基酸的瘤胃降解特性。以6头装有永久瘤胃瘘管的小尾寒羊为试验动物，用尼龙袋法测定不同生育期多年生黑麦草和紫羊茅在绵羊瘤胃降解前后粗蛋白、总氨基酸及各种氨基酸含量的变化。1）除开花期外，多年生黑麦草在各个生育期的粗蛋白及总氨基酸含量均高于紫羊茅；2种牧草都富含脯氨酸、谷氨酸、天冬氨酸、亮氨酸和缬氨酸，而含硫氨基酸含量较低；粗蛋白和总氨基酸含量均随生育期的延长呈下降趋势，即在分蘖期最高，在成熟期最低。2）2种牧草各氨基酸在分蘖期易降解，而在成熟期不易降解。3）2种牧草中的甘氨酸、脯氨酸、酪氨酸、精氨酸、苏氨酸、赖氨酸和苯丙氨酸在瘤胃中较易降解(P＜0.05)；多年生黑麦草中的天冬氨酸、丝氨酸、谷氨酸、缬氨酸、异亮氨酸和亮氨酸在瘤胃中不易降解（P＜0.05），紫羊茅中的丝氨酸、异亮氨酸和亮氨酸在瘤胃中不易降解（P＜0.05）。2种牧草的粗蛋白和氨基酸含量受品种和生育期影响较大，氨基酸在瘤胃中的降解程度与牧草生育期有关。

English. This research was to study the changes of amino acid profiles rumen degradation for ryegrass and red fescue. Six sheep fitted with permanent ruminal cannulas were used to determine the degradation characteristics of crude protein (CP), tatal amino acid (TAA) and amino acid (AA) ruminal incubation by nylon-bag technique for 2 forage grasses at different growth stages. 1) The contents of CP/TAA of ryegrass were higher than that of fescue except at flowering period, 2 kinds of grass were rich in proline, glutamic acid, aspartic acid, leucine, low sulfur amino acid; crude protein, total amino acid content showed downtrend (It was the highest in tillering period and lowest in mature period)at growth period. 2) The amino acids of 2 kinds of grass degradated in the tillering stage easily, but not in the mature stage. 3) Two kinds of grass glycine, proline, tyrosine, arginine, threonine, lysine and phenylalanine were more prone to degradation in the rumen (P＜0.05); aspartic acid, serine, glutamic acid, valine, isoleucine and leucine were not prone to degradation in the rumen for ryegrass (P0.05), serine, isoleucine, and leucine were not prone to degradation in the rumen for red fescue (P0.05). 2 kinds of grass crude protein and amino acids were affected by the great variety and growth stage; amino acid degradability in the rumen was related to the pasture growth periods.