Jonker Arjan, Yu Peiqiang
Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada.
Grasslands Research Centre, AgResearch Ltd., Tennent Drive, Private Bag 11008, Palmerston North 4442, New Zealand.
Int J Mol Sci. 2017 May 22;18(5):1105. doi: 10.3390/ijms18051105.
Forages grown in temperate regions, such as alfalfa ( L.) and white clover ( L.), typically have a high nutritional value when fed to ruminants. Their high protein content and degradation rate result, however, in poor utilization of protein from the forage resulting in excessive excretion of nitrogen into the environment by the animal. Proanthocyanindins (also known as condensed tannins) found in some forage legumes such as birdsfoot trefoil ( L.), bind to dietary protein and can improve protein utilization in the animal. This review will focus on (1) the occurrence of proanthocyanidins; (2) biosynthesis and structure of proanthocyanidins; (3) effects of proanthocyanidins on protein metabolism; (4) protein precipitating capacity of proanthocyanidins and their effects on true intestinal protein adsorption by ruminants; and (5) effect on animal health, animal performance and environmental emissions.
在温带地区种植的牧草，如紫花苜蓿（Medicago sativa L.）和白三叶草（Trifolium repens L.），喂给反刍动物时通常具有较高的营养价值。然而，它们的高蛋白含量和降解率导致牧草中的蛋白质利用率较低，从而使动物向环境中过量排泄氮。在一些豆科牧草如百脉根（Lotus corniculatus L.）中发现的原花青素（也称为缩合单宁），能与日粮中的蛋白质结合，并可提高动物对蛋白质的利用率。本综述将聚焦于：（1）原花青素的存在情况；（2）原花青素的生物合成与结构；（3）原花青素对蛋白质代谢的影响；（4）原花青素的蛋白质沉淀能力及其对反刍动物肠道真蛋白吸附的影响；以及（5）对动物健康、生产性能和环境排放的影响。
