Abstract
Lacticaseibacillus paracasei K56 (L. paracasei K56) is a probiotic with weight-loss effects. However, symbiosis research on the combined effects of Lacticaseibacillus paracasei K56 and prebiotics is lacking. Therefore, the aim of this study was to investigate the effects of L. paracasei K56, xylooligosaccharide (XOS), galactooligosaccharide (GOS), polyglucose (PG), and their synbiotic combinations (XOS + K56, GOS + K56, and PG + K56) on metabolism and gut composition in children with obesity, using an in vitro fermentation model. Fecal samples were collected from 14 children with obesity for in vitro fermentation, and the effects of the various treatments in gas production and short chain fatty acid synthesis (SCFAs) were assessed. Treatment with probiotics, prebiotics, and synbiotics regulated gut microbiota and metabolites in children with obesity. GOS and XOS had higher degradation rates than PG + K56 synbiotics in the gut microbiota of children with obesity. Moreover, treatment with XOS, GOS, and their synbiotic combinations, (XOS + K56) and (GOS + K56), significantly reduced the production of gas, propionic acid, and butyric acid compared with PG + K56 treatment. Treatments with GOS + K56 and XOS + K56 altered the composition of the gut microbiota, improved the abundance of Bifidobacteria and Lactobacilli, and reduced the abundance of Escherichia/Shigella. Overall, this study provides a theoretical foundation for the use of K56-based synbiotics.