de Boer G, Murphy J J, Kennelly J J
J Dairy Sci. 1987 May;70(5):977-82. doi: 10.3168/jds.S0022-0302(87)80102-9.
The objective was to develop a method for estimating intestinal availability of rumen undegradable protein. One-gram samples of six feedstuffs were placed into small (3.5 X 5.5 cm) nylon bags (pore size 48 micron). Bags were heat sealed and ruminally incubated in a polyester mesh (lingerie) bag in quadruplicate for each of six time periods (0, 2, 4, 8, 12, 24 h). Two bags from each rumen incubation time were inserted into the small intestine via a duodenal cannula at the rate of one bag per 45 min. Bags were mechanically washed either upon removal from the rumen--for determination of rumen degradability, or when recovered from the feces--for estimation of intestinal availability. Dried bags plus contents were digested intact for nitrogen analysis. Rumen degradable protein and apparent intestinal availability of undegradable protein (based on 8 h of rumen incubation) for corn gluten meal, fish meal, meat and bone meal, soybean meal, canola meal, and alfalfa hay, respectively, were 11.8, 95.0; 28.5, 82.8; 46.7, 73.0; 55.1, 99.3; 69.7, 79.2; and 68.8, 71.2. Results support the use of this technique as a rapid method for estimating both ruminal degradability, and intestinal availability of rumen undegradable protein.
目的是开发一种估计瘤胃不可降解蛋白质肠道可利用性的方法。将六种饲料的1克样品放入小（3.5×5.5厘米）尼龙袋（孔径48微米）中。袋子热封后，在聚酯网（内衣）袋中瘤胃培养，每种六个时间段（0、2、4、8、12、24小时）各重复四次。每个瘤胃培养时间的两个袋子通过十二指肠插管以每45分钟一个袋子的速度插入小肠。袋子从瘤胃取出时进行机械清洗——用于测定瘤胃降解率，或从粪便中回收时进行清洗——用于估计肠道可利用性。干燥的袋子及其内容物完整消化用于氮分析。玉米蛋白粉、鱼粉、肉骨粉、豆粕、菜籽粕和苜蓿干草的瘤胃可降解蛋白质和不可降解蛋白质的表观肠道可利用性（基于8小时瘤胃培养）分别为11.8、95.0；28.5、82.8；46.7、73.0；55.1、99.3；69.7、79.2；和68.8、71.2。结果支持将该技术用作估计瘤胃降解率和瘤胃不可降解蛋白质肠道可利用性的快速方法。
