Papas A M, Vicini J L, Clark J H, Peirce-Sandner S
J Nutr. 1984 Dec;114(12):2221-7. doi: 10.1093/jn/114.12.2221.
The effectiveness of an encapsulated rumen-protected methionine compound (RPMet) for delivering methionine postruminally and its effect on plasma amino acid concentrations, milk production and milk composition were evaluated. Thirty multiparous Holstein cows in early lactation were randomly assigned to five levels of RPMet. RPMet was supplied at 0, 550, 1100, 1650 or 3300 mg/kg of concentrate resulting in an intake of 0, 6.9, 12.9, 19.6 or 40.2 g of supplemental DL-methionine/day for each cow. The basal diet was alfalfa-bromegrass hay and a 15.8% crude protein corn- and soybean meal-based concentrate mixture. The experiment was divided into pretreatment and treatment periods, each consisting of 21 days. Feed intake and milk production were measured daily, milk composition weekly and plasma amino acid concentrations twice daily on days 17 and 20 of the pretreatment period and on days 4, 10 and 21 of the treatment period. RPMet was effective in delivering methionine postruminally, which increased concentrations of methionine in plasma. Dry matter intake, milk production, milk composition and body weight were not significantly affected by RPMet.
评估了一种包被的瘤胃保护性蛋氨酸化合物（RPMet）在瘤胃后释放蛋氨酸的效果及其对血浆氨基酸浓度、产奶量和牛奶成分的影响。30头处于泌乳早期的经产荷斯坦奶牛被随机分配到五个RPMet水平。RPMet的添加量分别为每千克精料0、550、1100、1650或3300毫克，每头奶牛每天补充的DL-蛋氨酸摄入量分别为0、6.9、12.9、19.6或40.2克。基础日粮为苜蓿-雀麦干草以及一种以玉米和豆粕为基础、粗蛋白含量为15.8%的精料混合物。试验分为预处理期和处理期，每期均为21天。在预处理期的第17天和第20天以及处理期的第4天、第10天和第21天，每天测量采食量和产奶量，每周测量牛奶成分，每天测量两次血浆氨基酸浓度。RPMet在瘤胃后释放蛋氨酸方面是有效的，它提高了血浆中蛋氨酸的浓度。RPMet对干物质采食量、产奶量、牛奶成分和体重没有显著影响。
