Von Keyserlingk M A, Shelford J A, Puchala R, Swift M L, Fisher L J
Department of Animal Science, University of British Columbia, Vancouver, Canada.
J Dairy Sci. 1998 Jan;81(1):140-9. doi: 10.3168/jds.S0022-0302(98)75561-4.
Nineteen grass silages were evaluated using the in situ rumen and mobile nylon bag techniques to determine the amino acid (AA) composition of rumen-undegradable protein and the possibility of predicting the concentrations of individual AA presented to the duodenum from the dietary AA profiles. All feeds and residues from the nylon bags were analyzed for diaminopimelic acid to correct for contamination by microbial proteins. All essential AA behaved similarly; the initial feed had the highest concentrations, and the material remaining in the mobile nylon bag had the lowest concentrations. The reduction in the concentration of methionine between the 12-h rumen residue and the residue in the mobile nylon bag was significant. With the exception of arginine (r2 = 0.76) and serine (r2 = 0.82), the relationship was poor between the concentrations of AA in the grass silage and those in the residue in the nylon bag following 12 h of rumen incubation. The lack of reliable relationships between concentrations of individual AA in the silages and concentrations of AA in the 12-h rumen residue indicated that degradability characteristics of AA in grass silage were not alike. This poor relationship was likely the reason that prediction equations could not be developed between the AA composition of the initial feed and the pattern of AA presented to the duodenum following 12 h of rumen incubation. The AA composition of the rumen-undegradable portion of grass silages differs from the AA composition of grass silages.
采用瘤胃原位和移动尼龙袋技术对19种青草青贮饲料进行评估，以确定瘤胃不可降解蛋白质的氨基酸（AA）组成，以及根据日粮氨基酸谱预测进入十二指肠的单个氨基酸浓度的可能性。对尼龙袋中的所有饲料和残留物进行二氨基庚二酸分析，以校正微生物蛋白质的污染。所有必需氨基酸的表现相似；初始饲料中的浓度最高，移动尼龙袋中残留的物质浓度最低。12小时瘤胃残留物与移动尼龙袋中残留物之间蛋氨酸浓度的降低显著。除精氨酸（r2 = 0.76）和丝氨酸（r2 = 0.82）外，青草青贮饲料中氨基酸浓度与瘤胃培养12小时后尼龙袋中残留物的氨基酸浓度之间的关系较差。青贮饲料中单个氨基酸浓度与12小时瘤胃残留物中氨基酸浓度之间缺乏可靠的关系，这表明青草青贮饲料中氨基酸的降解特性并不相同。这种较差的关系可能是无法在初始饲料的氨基酸组成与瘤胃培养12小时后进入十二指肠的氨基酸模式之间建立预测方程的原因。青草青贮饲料瘤胃不可降解部分的氨基酸组成与青草青贮饲料的氨基酸组成不同。
