Photomicrographs and scanning electron micrographs of posterior intestine of rainbow trout indicating no signs of damage to tissues when fed with experimental and control diets.

Images A-C represent control fed fish, A) cross section of intestine with AB-vG staining (x40 objective, scale bar is 100 μm), arrows indicate different structures including: goblet cell (GC), muscularis (Ms) and mucosal fold length (MFL); B) scanning electron micrograph showing section of posterior intestine (scale bar is 10 μm); C) scanning electron micrograph of microvilli of intestine (scale bar is 1 μm). Images D-F represent fish fed MsYF continuously; Images H-J represent fish fed MsYF pulsed with control every 2 weeks.