dr.ir. S (Sonja) de Vries

dr.ir. S (Sonja) de Vries

Universitair Docent

Research expertise

My research ambition is to understand the digestive physiology of monogastric animals. My research focusses at quantitative nutrition of pigs and poultry, digestion kinetics, processing technologies, enzymes, and nutritional modelling, with special emphasis on dietary fiber and fiber-rich ingredients.

Dietary fibers largely influence digestive process, as physicochemical properties of digesta, digesta transit, and microbial colonization, thereby affecting degradation and absorption of other nutrients. Hence, fibers play an important role in nutrition, and understanding the interactions between dietary fibers and digestive processes is crucial to predict the nutritional values of diets. Currently, I am involved in several multidisciplinary projects, where we study the interaction between dietary fiber and various digestive processes.

Already during my PhD, I got fascinated by the unique digestive system of poultry. Feeding diets with high fiber contents, we encountered issues that are usually not noticed when standard poultry diets are fed. The data indicated that high fiber diets exacerbate the separation of solid and liquid gut contents, possibly because of reverse flow of gut contents (reflux). In previous projects we elaborated on this research studying the passage of feed through the digestive tract in chickens, including the effects of fibers on digesta retention time. The recent award of a personal Veni grant, allows me to further elaborate on this research topic. I believe that insights in the (reverse) transport of digesta in poultry, and the role of fiber in its regulation, will be valuable to improve our understanding of digestive physiology in birds and other monogastric species.



I obtained my BSc and MSc degrees in Animal Sciences and PhD degree in Animal Nutrition at Wageningen University. My PhD research focused on the degradation of fiber in pigs and poultry, with special emphasis on Dried Distillers Grains with Solubles (DDGS) and rapeseed meal and effects of processing technologies and enzymes on fiber fractions. This work was part of a joint project between the Animal Nutrition Group and Laboratory of Food Chemistry, supervised by Prof. Dr ir W.J.J. Gerrits, Dr ir M.A. Kabel, and Prof. Dr ir W.H. Hendriks. After my graduation I continued research at the Ingredient Research Centre of Trouw Nutrition R&D, focusing on feed evaluation of monogastrics. In my current appointment as Assistant Professor at the Animal Nutrition Group of Wageningen University, I lead research projects and take care of education in the area of digestive physiology of monogastrics.