In situ evaluation of the protein value of wheat grain corrected for ruminal microbial contamination

Abstract

BACKGROUND: Uncorrected and microbial corrected in situ estimates of ruminal effective degradability (RED) of dry matter (DM), organic matter (OM) and crude protein (CP) and intestinal effective digestibility (IED) of DM and CP of a wheat grain sample were obtained by a simplified method using a sample pooled from rumen-incubated residues representing rumen outflow of undegraded food. Uncorrected values of RED of DM and CP were also obtained by the usual mathematical integration method. The study was performed in three rumen and duodenum cannulated wethers.

Effects of the ruminal comminution rate and microbial contamination of particles on accuracy of in situ estimates of ruminal degradability and intestinal digestibility of feedstuffs

“…The similar, or close, uncorrected estimates of RUCP obtained with both methods agree with results obtained by our group using only k p (Gonzá lez et al, 2006aArroyo et al, 2009). The proposed method has advantages compared to mathematical integration-based methods to obtain effective estimates of both ruminally undegraded fractions and intestinal digestibility: (i) increasing feed fractions simultaneously tested owing to the larger available samples, (ii) large reductions in the number of samples to incubate in the intestine, in analyses derived from ruminal and intestinal incubations and in the kinetics to be fitted and (iii) simplified microbial contamination correction of estimates of ruminally undegraded fractions and IED.…”

“…Thus, decreased IED estimates when k c is used are in agreement with the increase in the proportion of undigestible feed compounds associated with the extent of degradative actions with increased rumen residence time (González et al., 1999). As adherent micro‐organisms are mostly digested during intestinal incubation, the lack of correction of the microbial contamination in the rumen is also associated with IED overestimations, as shown by Arroyo et al. (2009) and González et al.…”

Ruminal degradation of cell wall associated nitrogenous compounds of several15N-labelled feeds

“…The intermediate k d value of DM‐SS between those NDF and ADF could be associated with the toxicity for microorganisms derived from the seed‐fat fermentation, which should limit the degradation progression. For DM, degradation parameters and ED estimates are in acceptable agreement with previous literature data for SS, WG and WS . Present ED estimates for NDF in the latter feed also agree with those indicated by these authors …”

In situ starch and crude protein degradation in the rumen and in vitro gas production kinetics of wheat genotypes

“…Several in situ experiments have studied the ruminal degradation of wheat grain, either in comparison with other grain types or as influenced by different growing and/or processing methods (Arieli et al., ; Givens et al., ; Michalet‐Doreau et al., ; Philippeau et al., ; Turgut et al., ; de Campeneere et al., ; Lund et al., ; Arroyo et al., ). To our knowledge, only three studies compared the in situ degradation of different wheat grain genotypes (Garnsworthy and Wiseman, ; Swan et al., ; McAllister and Sultana, ), and only two studies investigated the gas production (GP) kinetics of a set of different genotypes of wheat grains (Lanzas et al., ; Pozdíšek and Vaculová, ).…”