Maiga H A, Schingoethe D J, Henson J E
Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.
J Dairy Sci. 1996 Sep;79(9):1647-53. doi: 10.3168/jds.S0022-0302(96)76528-1.
Two ruminally cannulated Holstein cows (approximately 202 DIM) were used to determine the in situ degradability of five protein supplements: blood meal, meat and bone meal, corn gluten meal, expeller soybean meal, and solvent extracted soybean meal. Dacron bags containing 4 g of each supplement in duplicate were soaked in water and then incubated in the rumen for 0, 3, 6, 12, 18, and 24 h for 3 d. Four extra sample bags of each supplement were incubated in the rumen for 12 h to determine the in vitro intestinal digestibility and AA analysis of the residues. Protein supplements were also analyzed for their AA content. Ruminal degradability of individual supplements varied. Solvent soybean meal was the most degradable, and blood meal was the least degradable. Specific first-limiting essential AA were isoleucine for blood meal and meat and bone meal, lysine for corn gluten meal, and methionine for the soybean meals. The RUP fraction in solvent-extracted and expeller soybean meals tended to be more intestinally digestible than did the protein in blood meal and meat and bone meal. In general, all protein supplements, except solvent-extracted soybean meal, were high in RUP and had the potential to provide good quality AA to complement microbial AA for production.
选用两头安装了瘤胃瘘管的荷斯坦奶牛（泌乳天数约为202天）来测定5种蛋白质补充料的瘤胃原位降解率，这5种蛋白质补充料分别为血粉、肉骨粉、玉米蛋白粉、压榨豆粕和溶剂浸出豆粕。将装有4克每种补充料的涤纶袋一式两份浸泡在水中，然后在瘤胃中培养3天，分别培养0、3、6、12、18和24小时。每种补充料额外取4个样本袋在瘤胃中培养12小时，以测定残留物的体外肠道消化率和氨基酸分析。同时对蛋白质补充料的氨基酸含量进行分析。各补充料的瘤胃降解率各不相同。溶剂浸出豆粕的降解率最高，血粉的降解率最低。血粉和肉骨粉的第一限制性必需氨基酸为异亮氨酸，玉米蛋白粉为赖氨酸，豆粕为蛋氨酸。溶剂浸出豆粕和压榨豆粕中的瘤胃非降解蛋白部分在肠道中的消化率往往高于血粉和肉骨粉中的蛋白质。总体而言，除溶剂浸出豆粕外，所有蛋白质补充料的瘤胃非降解蛋白含量都很高，有潜力提供优质氨基酸来补充微生物氨基酸，以促进生产。
