In vitro assessment of gastrointestinal tract (GIT) fermentation in pigs: Fermentable substrates and microbial activity Barbara A. Williams, Marlou W. Bosch, Ajay Awati, Sergey R. Konstantinov, Hauke Smidt, Antoon D.L. Akkermans, Martin W.A. Verstegen and Seerp Tamminga Anim. Res., 54 3 (2005) 191-201 DOI: 10.1051/animres:2005011