[PDF] Characterization of In Situ Dry Matter and Nitrogen Digestion of

How accurate are in vitro and in situ digestion techniques?

In vitro and in situ techniques are used widely to estimate digestibility and rumendegradability,andtostudyruminal fermentation.Itis difficulttoappraise the accuracy of many of these techniques. Only the in vitro digestibility tech- nique was developed following calibration and validation of the in vitro estima- tions against the in vivo values.

What is the goal of in vitro and in situ methods?

The goal of most in vitro and in situ techniques is to estimate total-tract digestibility or rumen degradability. It is very unlikely that values measured in vitro are identical to the intended in vivo values, and thus mathematical modelling is a useful tool to link the data obtained in vitro or in situ with the processes occurring in vivo.

How do in situ and in vitro gas production profiles compare?

0þ U (4:10) for in vitro gas production profiles. Although ranking of and comparisons between feeds according to their in situ or in vitro E values are similar, the estimates of E values obtained using the in situ technique are numerically greater than those obtained using the in vitro gas production method (Lo´pez et al., 1998, 2000).

How is digestibility estimated in the small intestine?

Methods to Estimate Post-Ruminal Digestibility Some in vitro techniques have been designed to estimate digestibility (mainly of the feed protein) in the small intestine (Calsamiglia et al., 2000). These tech- niques are based on the use of enzymes to simulate abomasal and intestinal digestion (Stern et al., 1997).