DisplayTitle

Temperature Resistance of Xylanase Inhibitors and the Presence of Grain-Associated Xylanases Affect the Activity of Exogenous Xylanases Added to Pelleted Wheat-Based Feeds

¹Nutrition and Health, Department of Biosystems, KU Leuven, Kasteelpark Arenberg 30, 3001 Heverlee, Belgium. ²Kemin Europa N.V., Toekomstlaan 42, 2200, Herentals, Belgium. ³Corresponding author. Phone: +32 14 28 62 00. E-mail: natasja.smeets@kemin.com ⁴Leuven Food Science and Nutrition Research Centre (LFoRCe), KU Leuven, Kasteelpark Arenberg 20, 3001 Heverlee , Belgium. ⁵KU Leuven, Faculty of Engineering Technology, Department of Microbial and Molecular Systems (M²S), Lab4Food, Kleinhoefstraat 4, 2440 Geel, Belgium.

The addition of exogenous xylanases (EX-XYL) to wheat-based poultry feeds is a common practice today. Wheat contains xylanase inhibitors (XI) and grain-associated xylanases (GA-XYL), which could affect the action of the EX-XYL. In this study, both GA-XYL and XI activity in feeding-quality wheat were assessed. In addition, the effect of the conditions during digestion in monogastrics and the effects of pelleting at different conditioning temperatures on GA-XYL and XI were investigated. The GA-XYL activity varied between no activity and 0.821 XU/g. In contrast, the XI activity was consistently high in all wheat samples and ranged between 259 and 331 IU/g. Simulating the digestive process did not affect the activities of GA-XYL or XI. Pelleting at 85°C or higher reduced the XI activity up to 46%. GA-XYL, however, were more heat-sensitive, and their activity was reduced to 67% at 60°C. The extract viscosity increased and the release of reducing sugars decreased at higher conditioning temperatures. In addition, the net effect of EX-XYL on extract viscosity increased at higher temperatures, whereas the release of reducing sugars was not affected. In conclusion, XI affected the action of EX-XYL during the digestive process, and pelleting did not eliminate their negative effects.