This thesis aimed at identifying limiting factors in the degradability of fiber fractions in pigs and poultry and at development of technologies to improve their degradation. Focus was on recalcitrant fiber structures as found in in maize dried distillers grain with solubles (DDGS) and rapeseed meal (RSM).
The increased use of fiber-rich feedstuffs in pig and poultry diets requires an optimal utilization of these ingredients. Hence, the animal feed industry explores opportunities to improve degradability of these feedstuffs and maximize their inclusion levels in pig and poultry diets. Processing and enzyme technologies can modify the physicochemical characteristics of fiber fractions from feed ingredients, thereby affecting their degradability. In this way, fermentability of non-starch polysaccharides (NSP) and thus their potential energetic utilization might be enhanced. In addition, technologies can be aimed at alleviation of adverse effects on digestion and absorption of other nutrients, which might be particularly of interest for young pigs and poultry. However, to understand modifications that occur during processing detailed information on the composition of fiber structures is required.
Fiber degradation in growing pigs and broilers was studied in detail and limiting structures in the degradation of NSP were identified. Effects of processing and enzyme technologies on fiber-rich feedstuffs were evaluated based on literature and in vitro and in vivo studies in growing pigs and broilers. In addition, marker methods to study digestibility of fiber-rich diets in broilers were discussed. Finally, interactive effects between specific fermentable fiber sources and the digestive utilization of the diet were investigated.