天山西部高山区夏季放牧草地4种重要牧草营养品质评价

为综合评价天山西部高山区夏季放牧草地4种重要牧草的营养品质,本研究设定在具有代表性的天山西部沙尔套山高山区(2800~3400m)夏季牧场,对分布在该区域的重要优势种牧草线叶嵩草、细果苔草、西伯利亚羽衣草和高山地榆进行分析。通过对其营养价值、消化率的测定及体外产气模型参数的估计。结果表明,各牧草在粗纤维和粗脂肪含量上均无显著差异(P0.05)。细果苔草的中性洗涤纤维(P=0.048)和酸性洗涤纤维(P=0.005)含量均最高。西伯利亚羽衣草粗灰分(P=0.037)含量最高,延滞时间(P=0.005)较长。高山地榆粗蛋白(P0.0001)、钙(P=0.001)和磷(P=0.004)的含量均最高,且有机物消化率(P=0.003)、代谢能(P=0.001)、理论最大产气量(P=0.067)和产气速率(P=0.079)也最高。线叶嵩草仅干物质(P=0.001)含量最高。最后采用主成分分析法综合14项指标,评价出4种牧草的综合营养价值,按优劣排序为:高山地榆西伯利亚羽衣草线叶嵩草细果苔草。

Nutritional quality of four important herbage species in summer grazing grassland in the alpine zone,west Tianshan Mountain

The aim of this study was to evaluate the nutritional quality of four important herbage species growing in summer alpine pasture in the western region of Tianshan Mountain.We determined the nutritive value,digestibility,and parameters of in vitro gas production for four typical herbages (Kobresia capillifolia,Carex stenocarpa,Alchemilla sibirica,and Sanguisorbs alpina) growing in summer pasture on Shaertao mountain (2800-3400 m above sea level),west Tianshan.The contents of crude fiber and crude fat did not differ significantly among the four herbage species (P＞0.05).C.lasiocarpa had the highest contents of acid detergent fiber (P=0.048) and neutral detergent fiber (P=0.005).A.sibirica had the highest content of crude ash (P=0.037) and the longest delay time (P=0.005).S.alpina had the highest contents of crude protein (P＜0.0001),calcium (P=0.001),and phosphorus (P=0.004),the most digestible organic matter (P=0.003),and the highest metabolic energy (P=0.067) and gas production rate (P=0.079).K.capillifolia had the highest dry matter content (P=0.001).The results of a principal component analysis based on the 14 main indexes of nutritional quality indicated that the four herbages were ranked,from highest nutritional value to lowest,as follows:S.alpine＞A.sibirica＞K.capillifolia＞C.stenocarpa.