the dietary constituents—proteins, lipids and carbohydrates. Otherwise, clustered and undigested starch granules were concentrated and easily observed in fecal samples (e.g., Fig. 4O). Starch digestibility and fecal starch granule abundance followed an inverse trend. Fecal concentra- tion of starch granules was higher in jundiá than in tilapia, particularly in fish fed ground corn and broken rice diets, and agrees with the starch ADC measured for both species. Fecal starch granules showed pores and concentric circles as evidence of enzymatic attack, as previously report- ed (Dhital et al., 2010; Jiang et al., 2011; Li et al., 2013). The lower dry matter ADC observed in both fish species fed wheat bran and cassava residue was corroborated in jundiá through scanning electron micros- copy, in which a higher concentration of cell walls (fiber) was seen in fecal samples (figure not presented).