Descripción
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Estimates of ruminal effective degradability (RED) and intestinal effective digestibility (IED) for DM, CP and AA were obtained by a simplified in situ method using a sample pooled from rumen-incubated residues that represented the rumen outflow of undegraded feed. The effect of microbial contamination that took place in the rumen was corrected using 15N 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 composited samples of SBM, BG and LH were, respectively, 1.60%, 11.1% and 24.4% of total N. However, intestinal incubation eliminated this microbial charge by 99.8%, 98.8% and 87.9%, respectively. With microbial corrections, RED showed an increase, and IED showed a decrease, except in SBM. Estimates of feed metabolizable (or intestinal digested) CP were reduced with this correction by 1.55% in SBM, 13.4% in BG and 34.0% in LH. The range of variation for corrected RED of AA was minimal in BG (76.7 to 81.7%), intermediate in SBM (40.1 to 49.7%) and maximal in LH (74.6 to 88.5%). Corrected IED of AA were relatively similar in SBM (97.0 to 99.5%). However, large variations were observed in BG (73.9 to 93.0%) and in LH (9.75 to 88.0%). In all feeds, maximum IED values corresponded to phenylalanine, and minimum values to glycine and cysteine. Digestion in the rumen and intestine changed the profiles of essential AA. Overall, our results support that AA digestion is affected by the characteristics of their radicals and their contents in plant cell wall proteins. Accurate estimates of feed metabolizable AA or protein require 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. | |
Internacional
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Si |
JCR del ISI
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Si |
Título de la revista
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ARCHIVES OF ANIMAL NUTRITION |
ISSN
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1745-039X |
Factor de impacto JCR
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0,893 |
Información de impacto
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Volumen
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63 |
DOI
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Número de revista
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0 |
Desde la página
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304 |
Hasta la página
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320 |
Mes
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ENERO |
Ranking
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