Ammonia treatment of wheat straw. 2? Efficiency of microbial protein synthesis, rumen microbial protein pool size and turnover, and small intestinal protein digestion in sheep

Authors

  • S.J. Oosting
  • T.C. Viets
  • S.C.W. Lammers-Wienhoven
  • J. Van Bruchem

DOI:

https://doi.org/10.18174/njas.v41i2.627

Abstract

Ammonia-treated wheat straw (AWS) was compared with untreated wheat straw (UWS) and untreated wheat straw supplemented with urea (SWS) in an experiment with 6 wether sheep. Microbial protein synthesis increased after ammonia treatment due to the higher intake of rumen degradable organic matter (OM). The efficiency of microbial protein synthesis was low for all diets, averaging 22.1 g N/kg apparently rumen degradable OM and was not significantly affected by ammonia treatment. Estimates of microbial protein synthesis based on diaminopimelic acid or the amino acid profile methods did not differ significantly. The pool of microbial DM (average, 151 g) and N (12 g) in the rumen and the proportion of rumen microorganisms associated with the fluid phase (average, 36%) were not affected by diet, but the clearance rate (%/h) of microorganisms tended (P<0.10) to be higher for AWS (2.9) than for UWS (2.1) and SWS (2.2). True rumen degradation of dietary amino acid-N (AA-N) was not affected by diet (average, 412 g/kg). Small intestinal apparent digestibilities of N, AA-N, amino acids and non-protein nitrogen did not differ significantly among diets and were on average 485, 583, 593 and 313 g/kg, respectively. Apparent small intestinal AA-N absorption (g/day) was significantly higher for AWS (6.0) than for UWS (3.8) and SWS (4.2).

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Published

1993-06-01

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Section

Papers