The use of carbohydrases and proteases in poultry production occasionally results
in inconsistent physiological responses that are difficult to explain. However,
it has previously been demonstrated that a substantial portion of the variation
in enzyme efficacy is associated with the inherent ileal digestibility of
starch, protein and lipid, and so an appreciation for the concentration of the
undigested fractions of these nutrients in a diet may help to determine the
magnitude and consistency of feed enzyme responses. Considering that the expense
of in vivo physiological assays for the assessment of enzyme
functional pattern is high, it is crucial to develop suitable in
vitro methods to predict the magnitude of enzyme response. The purpose
of the current paper is to describe inherent characteristics of poultry diets
and feed ingredients in response to carbohydrases and proteases in order to aid
the development of in vitro assays to predict feed enzyme
functional patterns.