两种野生木本植物饲用价值研究

Study on Feeding Value of Two Species of Wild Woody Plants

为评价野生银合欢和构树两种木本植物的饲用价值,测定了两者上部幼嫩茎叶青贮前后的营养成分,进行青贮前后营养价值比较和饲喂文山牛适口性评定。结果表明:银合欢和构树幼嫩茎叶青贮前均属于粗蛋白含量高、粗纤维含量低的优质木本饲料;经60 d青贮后,营养品质较青贮前显著提高,干物质、粗纤维、可溶性碳水化合物、中性洗涤纤维、酸性洗涤纤维均降低,粗蛋白、粗灰分、木质素、可消化干物质、干物质采食量和饲料相对值均增加,银合欢的饲料相对值(RFV)提高了27.64%,构树提高了49.93%,单宁含量均在1%以下。参考美国牧草和草地协会干草质量标准评定,银合欢青贮前为4级,青贮后达到2级,构树青贮前为2级,青贮后达到1级,青贮显著提高了两者的营养品质(P<0.05)。通过文山牛适口性测定表明,银合欢青贮前采食量仅38%,青贮后采食量100%,且采食时间大幅缩短;构树青贮前后采食量均为100%,青贮后的采食时间较青贮前缩短。综上,通过青贮方式能显著提高银合欢和构树二者的营养品质和适口性。

In order to evaluate the feeding value of wild Leucaena leucocephala and Broussonetia papyrifera,the nutritional components of tender stem and leaf in the upper part of tree before and after silage were determined,to compare the changes of nutritional values and to evaluate the palatability before and after silage for Wenshan cattle.The results showed that both Leucaena leucocephala and Broussonetia papyrifera belonged to high-quality woody forage with high crude protein and low crude fiber content before silage.After 60 days silage,the nutritional quality of Leucaena leucocephala and Broussonetia papyrifera were significantly higher than those before silage,the dry matter,crude fiber,soluble carbohydrate,neutral washing fiber,acid washing fiber and index were reduced,while the crude protein,crude ash,lignin,digestible dry matter and RFV were increased.The RFVs of Leucaena leucocephala and Broussonetia leucocephala increased by 27.64% and by 49.93%,and the tannin content dropped below 1%.According to the hay quality standard of American Herbage and grassland Association,Leucaena leucocephala before silage was classified as grade Ⅳ,of which it reached grade Ⅱ after silage;at the same time,Broussonetia leucocephala before silage was classified as grade Ⅱ,of which it reached gradeⅠafter silage,showing that the nutritional quality of both Leucaena leucocephala and Broussonetia papyrifera were improved by silage(P<0.05).Through the palatability trial for beef cattle,the intake rate of Leucaena leucocephala before silage was only 38% while the intake rate after silage was 100% and the feeding time was sharply shorten for Wenshan cattle;the intake rates of Broussonetia leucocephala before or after silage were 100% while the feeding time was also shorten for beef cattle.In brief,the silage could significantly improve the nutritional quality and palatability for both Leucaena leucocephala and Broussonetia papyrifera.