## 3 Results
### Microbial Community Composition  
The Simpson diversity index revealed that supplementation with the different test products strongly enhanced microbial diversity. The strongest effects were observed in the luminal PC, reaching significance for Donor A, Donor B, and when the values for the two donors were averaged (\(p<0.05\) for all) (Table 1). When the values for the two donors were averaged, the LCM was the only test product that resulted in a significant increase in the Simpson diversity index in the lumen and mucus DC compared with the control period while treatment with the other three test products, BBM, OSM, and KC, resulted in a significant increase in the mucosal PC compared with the control period. Figure 2: Changes in ammonium and bSCFA levels with treatment for (**A**) Donor A, ammonium; (**B**) Donor A, bSCFA; (**C**) Donor B, ammonium; (**D**) Donor B, bSCFA. * Indicates statistically significant differences relative to the control period while different letters indicate a statistical difference between different treatments, i.e., different letters for different columns indicates that the values in the columns are statistically significantly different while those marked with the same letter are not; \(p<0.05\). BBM = Berry Blast Muffin; DC = distal colon; KC = Kodiak Cake; LCM = Lemon Chia Muffin; OSM = Oat Spice Mookie; PC = proximal colon. The relative abundance of the microbial community at the phylum level for the lumen is shown in Figure 3. In the luminal PC, supplementation resulted in a significant increase (\(p<0.05\)) in the relative abundance of Proteobacteria for both donors between the control and treatment periods for all four test products (Figure 3A,B). The relative abundance of Actinobacteria was significantly decreased (\(p<0.05\)) with all test products except for the KC for Donor A and with all test products for Donor B. Additionally, the relative abundance of Bacteroidetes was significantly increased (\(p<0.05\)) with the KC product in the luminal PC for Donor B. In the luminal DC of Donor A, the relative abundance of Bacteroidetes was significantly decreased (\(p<0.05\)) between the control and treatment periods with all test products and the relative abundance of Proteobacteria was significantly increased (\(p<0.05\)) for all test products except the BBM (Figure 3C,D). The relative abundances of Verrucomicrobia and Actinobacteria were also significantly increased (\(p<0.05\)) with the OSM product. For Donor B, the relative abundance of Actinobacteria was significantly decreased (\(p<0.05\)) between the control and treatment periods with all test products, that of Proteobacteria was significantly increased (\(p<0.05\)) with LCM, and that of Firmicutes was significantly increased (\(p<0.05\)), while Verrucomicrobia and Bacteroidetes were significantly decreased (\(p<0.05\)) with the KC product. Overall, there were fewer changes in the relative abundance at the phylum level in the mucosal PC and DC compared with the lumen (Figure S1). Relative abundance at the family level for the lumen is shown in Figure 4. While the phylum Bacteroidetes did not significantly expand in the luminal PC, at the species level Bacteroidetes tended to decrease while Tannerellaceae and Rikenellaceae tended to increase from the control period to the treatment period for each of the test products and with both donors (Figure 4A,B). Also in the luminal PC, the expansion of Proteobacteria after supplementation with the test products was largely due to the expansion of Enterobacteriaceae. The expansion of Proteobacteria in the luminal DC with supplementation was also largely due to Enterobacteriaceaeae with all test products; other changes between the control and treatment period were variable among the test products (Figure 4C,D). There were few changes at the species level in the mucosal PC and DC (Figure S2).