Sykes A R, Coop R L
Animal and Food Sciences Division, PO Box 84, Lincoln University, Canterbury New Zealand.
N Z Vet J. 2001 Dec;49(6):222-6. doi: 10.1080/00480169.2001.36236.
Effects of gastrointestinal nematode infection on metabolism and nutrient utilisation in sheep are reviewed. Infection induces protein deficiency by increasing the demand for amino acids in the alimentary tract while reducing supply through depression of appetite. Mechanisms through which improved protein nutrition could improve the performance of the host are then discussed. Opportunities for capitalising on such effects are limited by our rudimentary understanding of the cell-mediated immune response in gastrointestinal epithelial tissue. Both resistance of the animal to larval establishment and performance in the face of larval challenge can be enhanced by improved protein nutrition. However, enhanced immune responses may not necessarily be synonymous with improved productivity except at luxurious levels of protein intake, because of apparently competing demands for protein. Such levels of protein nutrition are difficult to achieve in pasture-based systems, because of the protein limiting role of the rumen. Work with proteinprotecting tannins to overcome this limitation is discussed. The much more limited evidence for effect of mineral nutrition, particularly copper (Cu), molybdenum (Mo), cobalt (Co) and phosphorus (P), on outcome of larval challenge is also reviewed.
本文综述了胃肠道线虫感染对绵羊新陈代谢和营养利用的影响。感染通过增加消化道对氨基酸的需求，同时因食欲下降减少供应，从而导致蛋白质缺乏。接着讨论了改善蛋白质营养可提高宿主性能的机制。利用这些影响的机会受到我们对胃肠道上皮组织细胞介导免疫反应的初步了解的限制。改善蛋白质营养可增强动物对幼虫定植的抵抗力以及面对幼虫攻击时的性能。然而，除了在蛋白质摄入量充足的情况下，增强的免疫反应不一定等同于提高的生产力，因为对蛋白质的需求显然存在竞争。由于瘤胃的蛋白质限制作用，在以牧场为基础的系统中很难达到这样的蛋白质营养水平。文中讨论了使用蛋白质保护单宁来克服这一限制的研究。还综述了关于矿物质营养，特别是铜（Cu）、钼（Mo）、钴（Co）和磷（P）对幼虫攻击结果影响的更为有限的证据。
