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Keywords:

  • ruminal degradability;
  • intestinal digestibility;
  • protein;
  • amino acids;
  • sheep

Abstract

BACKGROUND

Microbial corrected effective in situ estimates of ruminal undegraded fraction (RU) and intestinal effective digestibility (IED) of dry matter (DM), crude protein (CP) and amino acids (AA) of expeller palm kernel (EPK) and rapeseed meal (RSM) were measured on three rumen- and duodenum-cannulated wethers using 15N labelling techniques and considering ruminal rates of comminution (kc) and outflow (kp) of particles.

RESULTS

The lack of kc and microbial correction overestimated the RU of DM by 4.91% (EPK) and 9.88% (RSM). The lack of this correction also overestimated in both feeds the RU of CP, individual and total (TAA) AA as well as the IED of DM, CP, TAA and most AA. RU estimates were higher for CP than for TAA, but the opposite was observed for IED. The intestinal digested fraction was higher for CP than for TAA: 17.4% (EPK) and 13.8% (RSM). Digestion led to large changes in the essential AA profile in both feeds.

CONCLUSION

The lack of kc and microbial correction as well as CP-based results leads to considerable overestimations in the protein use of both feeds. Digestion aggravates the lysine deficiency of EPK but has global positive effects in the absorbed profile of RSM. © 2013 Society of Chemical Industry