Pregnant sows, especially in late pregnancy, are prone to constipation due to physiological and feed factors. Effects of isomaltooligosaccharide (IMO) and Bacillus on the fecal score during d 85 to 91 (A), d 92 to 98 (B), d 99 to 105 (C), and d 106 to 112 (D) of gestation of sows. Data are presented as means ± SD (n = 20). Values with different lowercase letters (a, b) are significantly different (P < 0.05). CON group, sows fed diets without IMO; IMO group, sows fed diets containing 5.0 g/kg IMO; IMOS group, sows fed diets containing 5.0 g/kg IMO plus 0.2 g/kg Bacillus subtilis; IMOL group, sows fed diets containing 5.0 g/kg IMO plus 0.2 g/kg Bacillus licheniformis; IMOSL group, sows fed diets containing 5.0 g/kg IMO plus 0.2 g/kg B. subtilis and 0.2 g/kg B. licheniformis.