González Javier, Ouarti Mafhoud, Rodríguez Carlos Alberto, Centeno Carmen
a Departamento de Producción Animal, Escuela Técnica Superior de Ingenieros Agrónomos , Universidad Politécnica de Madrid.
b Consejo Superior de Investigaciones Científicas, Instituto de Nutrición y Bromatología , Madrid , Spain.
Arch Anim Nutr. 2009;63(4):304-20. doi: 10.1080/17450390903020463.
The ruminal effective degradability (RED) and intestinal effective digestibility (IED) for dry matter, crude protein (CP) and amino acids (AA) were estimated by a simplified in situ method using pooled samples from rumen-incubated residues, which represented the ruminal outflow of undegraded feed. The effect of microbial contamination in the rumen was corrected using (15)N infusion techniques. Studies were carried out for soybean meal (SBM), barley grain (BG) and lucerne hay (LH) in three wethers cannulated in the rumen and the duodenum. Uncorrected values of RED for CP obtained either by mathematical integration or our simplified method were similar in all feeds. Microbial N in the pooled samples of SBM, BG and LH were 2%, 11% and 24% of total N, respectively. However, intestinal incubation eliminated this microbial charge by 100%, 99% and 88%, respectively. With microbial corrections, RED showed an increase, and IED showed a decrease, except for SBM. With this correction, intestinal digested CP was reduced by 2% in SBM, 13% in BG and 34% in LH. Corrected IED of AA was relatively similar in SBM (97-99%). However, large variations were observed in BG (74-93%) and in LH (10-88%). Digestion in the rumen and intestine changed the essential AA pattern. Overall, our results support that AA digestion is affected by the characteristics of their radicals and their contents in plant cell wall proteins. The accurate estimation of feed metabolisable AA or protein requires effective measures that are corrected by ruminal microbial contamination. The proposed in situ method largely simplifies these tasks and allows a more complete and less expensive feed evaluation.
采用简化的原位法，利用瘤胃培养残渣的混合样本（代表未降解饲料的瘤胃流出物）估算干物质、粗蛋白（CP）和氨基酸（AA）的瘤胃有效降解率（RED）和肠道有效消化率（IED）。使用（15）N注入技术校正瘤胃中微生物污染的影响。对三只安装了瘤胃和十二指肠瘘管的阉羊的豆粕（SBM）、大麦谷物（BG）和苜蓿干草（LH）进行了研究。通过数学积分或我们的简化方法获得的CP的未校正RED值在所有饲料中相似。SBM、BG和LH混合样本中的微生物氮分别占总氮的2%、11%和24%。然而，肠道培养分别消除了100%、99%和88%的这种微生物负荷。经过微生物校正后，除SBM外，RED有所增加，IED有所下降。经过这种校正，SBM中肠道消化的CP减少了2%，BG中减少了13%，LH中减少了34%。SBM中AA的校正IED相对相似（97-99%）。然而，BG（74-93%）和LH（10-88%）中观察到较大差异。瘤胃和肠道中的消化改变了必需氨基酸模式。总体而言，我们的结果支持氨基酸消化受其基团特征及其在植物细胞壁蛋白中的含量影响。准确估计饲料可代谢氨基酸或蛋白质需要通过瘤胃微生物污染校正的有效措施。所提出的原位方法大大简化了这些任务，并允许进行更完整且成本更低的饲料评估。
