潜在的饲料添加剂在瘤胃液中的稳定性.doc

毕 业 设 计（论 文）外 文 参 考 资 料 及 译 文 潜在的饲料添加剂在瘤胃液中的稳定性 学生姓名： 学　　号： 专　　业： 动物科学 所在学院： 动物科学与技术学院 指导教师： 职　　称： 副教授 Stability and stabilization of potential feed additive enzymes in rumen fluid Diego P. Morgavia, 1, C.James Newbolda，David E. Beeverb ，R.John Wallace Abstract Some activities, including the β-1,4-endoglucanase and xylanase from the extract derived from Aspergillus niger, were stable for at least 6 h in rumen fluid. The same activities in the other extracts also retained substantial activity for several hours. β-Glucosidase and β-xylosidase activities were much more labile. most being almost completely destroyed after 1. and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that most proteins in the extracts were digested extensively after up to 7 h of incubation. Adding bovine serum albumin (0.5 g/l) to the incubation increased the half-life of Trichoderma viride β-glucosidase activity from less than 0.5 h to 3 h. Proteins extracted from plant materials, particularly the soybean 7S globulin fraction, also conferred protection from proteolytic breakdown，but none was as effective as bovine serum albumin. It was concluded that the stability of most fibrolytic enzymes in rumen fluid, is not likely to be a limiting factor in the use of enzymes as feed additives for ruminants. but if the enzymes are not stable, means can be found for their stabilization. Keywords Enzymes; Ruminants; Cellulase; Xylanase; Stability; Proteolysis 1. Introduction Industrially produced enzymes are increasingly being used as feed additives to improve the nutritional efficiency of farm animals.. Their application in ruminant diets is still under development. Early results show promise, although many factors such as the precise nature of beneficial enzymes and the diet specificity of the response, remain