Continuous intake of galacto-oligosaccharides containing syrup contributes to maintaining the health of household cats by modulating their gut microbiota

The study of the relationships between the microbiota and intestinal environment of companion animals has gained increasing attention, particularly concerning health and disease. Previously, we demonstrated that continuous intake of galacto-oligosaccharides (GOS), a prebiotic, can improve the health of household dogs by modulating their gut microbiota. Given the potential health benefits of GOS in cats, we conducted a single-arm open-label study to evaluate the effects of a GOS-containing syrup on the gut microbiota and its metabolites in healthy cats. The study included 25 household cats and was conducted over 12 weeks. Each cat was fed 1.2 g of a GOS-containing syrup per day, equivalent to 0.5 g of GOS. Before the start of the study (week 0), during the 8-week intake period (weeks 4 and 8), and 4 weeks after the intake period (week 12), fecal microbiota, fecal organic acid and putrefactive product concentrations, fecal odor, and serum uremic toxin concentrations were assessed. The results showed that the levels of acetic acid-producing <i>Bifidobacteriaceae</i> significantly increased as a result of GOS intake. Additionally, <i>Peptostreptococcaceae</i> and <i>Eggerthellaceae</i> levels significantly decreased and increased, respectively, due to GOS intake. Furthermore, the concentrations of acetic, propionic, and <i>n-</i>butyric acids in feces significantly increased, whereas serum phenyl sulfate levels decreased significantly. These findings suggested that continuous GOS intake may contribute to the health of household cats.