The Synbiotic AG1 Outcompetes A Comparative Multi-strain Probiotic In The SHIME Model

AG1 is a synbiotic product that contains a unique blend of pre-/probiotics and phytochemicals, which can act as non-traditional prebiotics. We sought to compare the difference in fermentative and immunomodulatory effects between AG1 and a comparative multi-strain probiotic using the SHIME model (ProDigest, Belgium). Stool from 8 healthy adult donors were incubated with the simulated digestive byproducts of AG1, a CFU matched dose of a 12-strain commercial probiotic product, or a blank control for 48 hours. During the 48 hours of fermentation, changes in pH, gas pressure, lactate, total SCFAs, acetate, propionate, butyrate, bSCFAs, and ammonium were measured. The ferment was then added to a co-culture of Caco-2/THP-1 Blue cells and allowed to incubate for an additional 24 hours. Subsequently, lipopolysaccharide was applied to the co-culture to stimulate an immune response followed by a 6 hour incubation period. The change in electric resistance through the Caco-2 cells was measured to evaluate the barrier function of the cell line. Changes in NF-κB activity, IL-6, IL-10, IL-1β, TNF-ɑ, CXCL-10, MCP-1, and IL-8 were measured to assess changes in immune function following immune stimulation. All variables were evaluated for statistical significance using a repeated measures one-way ANOVA with Tukey’s multiple comparisons tests to assess between group differences. Results from the fermentation phase showed AG1 induced significant increases in the amount of total SCFAs (58.2 ± 9.9%), acetate (55.4 ± 8.2%), propionate (72.4 ± 23.7%), and butyrate (33.6 ± 35.5%) relative to the probiotic alone (p < 0.05). NF-κB (8.5 ± 5.5%), IL-10 (32.8 ± 15.6%), IL-1β (21.3 ± 16.5%), and IL-8 (4.7 ± 3.4%) also significantly increased when cells were treated with AG1 relative to the probiotic alone (p < 0.05). Transepithelial electrical resistance was significantly higher for the AG1 treated group relative to the probiotic alone (p < 0.05, 4.5 ± 1.2%) indicating the maintenance of the epithelial barrier. Together, these data indicate mechanistic level changes to support overall gut health and facilitate a normal immune response against endotoxin challenges. These findings help demonstrate that the combination of prebiotics with probiotics acutely leads to greater metabolic and physiological outcomes inferring greater health outcomes in the host. These findings also highlight that synbiotics may work better than either pre- or probiotics alone in acute dosing paradigms. This research was funded by AG1 (AG1, Carson City, NV). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.