Synbiotic VSL#3 and yacon-based product modulate the intestinal microbiota and prevent the development of pre-neoplastic lesions in a colorectal carcinogenesis model.

Colorectal cancer is a public health problem, with dysbiosis being one of the risk factors due to its role in intestinal inflammation. Probiotics and synbiotics have been used in order to restore the microbiota balance and to prevent colorectal carcinogenesis. We aimed to investigate the effects of the probiotic VSL#3® alone or in combination with a yacon-based prebiotic concentrate on the microbiota modulation and its influence on colorectal carcinogenesis in an animal model. C57BL/6J mice were divided into three groups: control (control diet), probiotic (control diet + VSL#3®), and synbiotic (yacon diet + VSL#3®). The diets were provided for 13 weeks and, from the third one, all animals were subjected to induction of colorectal cancer precursor lesions. Stool samples were collected to evaluate organic acids, feces pH, β-glucuronidase activity, and microbiota composition. The colon was used to count pre-neoplastic lesions and to determine the cytokines. The microbiota composition was influenced by the use of probiotic and synbiotic. Modifications were also observed in the abundance of bacterial genera with respect to the control group, which confirms the interference of carcinogenesis in the microbiota. Pre-neoplastic lesions were reduced by the use of the synbiotic, but not with the probiotic. The protection provided by the synbiotic can be attributed to the modulation of the intestinal inflammatory response, to the inhibition of a pro-carcinogenic enzyme, and to the production of organic acids. The modulation of the composition and activity of the microbiota contributed to beneficial changes in the intestinal microenvironment, which led to a reduction in carcinogenesis. KEY POINTS: • Synbiotic reduces the incidence of colorectal cancer precursor lesions. • Synbiotic modulates the composition and activity of intestinal microbiota. • Synbiotic increases the abundance of butyrate-producing bacteria.