Effects of Dietary Isomaltooligosaccharide Levels on the Gut Microbiota, Immune Function of Sows, and the Diarrhea Rate of Their Offspring.

To investigate the effects of dietary isomaltooligosaccharide (IMO) levels on the gut microbiota, immune function of sows, and the diarrhea rate of their offspring, 120 multiparous gestating pig improvement company (PIC) sows with similar body conditions were selected and fed 1 of 6 diets: a basal diet with no supplement (control, CON), or a diet supplemented with 2.5 g/kg, 5.0 g/kg, 10.0 g/kg, 20.0 g/kg, or 40.0 g/kg IMO (IMO1, IMO2, IMO3, IMO4, or IMO5 group, respectively). Results showed that dietary treatments did not affect the reproductive performance and colostrum composition of sows ( > 0.05). However, compared to the CON, IMO reduced the diarrhea rate of suckling piglets ( < 0.05) and improved the concentrations of colostrum IgA, IgG, and IgM ( < 0.05). Moreover, IMO decreased the concentrations of serum D-lactate (D-LA) and lipopolysaccharides (LPS) at farrowing and day 18 of lactation (L18) ( < 0.05). High-throughput pyrosequencing of the 16S rRNA demonstrated that IMO shaped the composition of gut microbiota in different reproductive stages (day 107 of gestation, G107; day 10 of lactation, L10) ( < 0.05). At the genus level, the relative abundance of g_ and g_ in G107 and g_, g_, g_, and g_ in L10 was increased in IMO groups but the g_ in G107 was decreased in IMO groups relative to the CON group ( < 0.05). Furthermore, the serum D-LA and LPS were negatively correlated with the genus g_ and g_ but positively correlated with the genus g_ and g_. Additionally, the colostrum IgA, IgG, and IgM of sows were positively correlated with the genus g_, g_, and g_ but negatively correlated with the genus g_. These findings indicated that IMO could promote the immune activation and had a significant influence in sows' gut microbiota during perinatal period, which may reduce the diarrhea rate of their offspring.