Enzymatic assays for xylanase and β-glucanase feed enzymes

The analysis of pure enzyme activities is well documented but few data have been published about the comparison of results between several laboratories. When the enzymes are mixed to an animal feed the dosage is difficult due to different interactions with the feed elements and to the dilution level. The results of the comparison of a xylanase and a β-glucanase assays of pure enzymes in three laboratories are disclosed. They show a good repeatability for both methods (CV = 7.2% and 7.0%, respectively for xylanase and β-glucanase activities) and a reproducibility equal to the one listed in the literature (16.6% and 19.3%, respectively). As the enzymes have been introduced in a feed, the methods were adapted to cope up with the restraints linked to the feed elements. In-feed methods are described for xylanase and β-glucanase activities that allow a monitoring of the active enzyme. They can be used for inclusion as well as for dispersal controls.