The effect of feeding cocoa powder and Lactobacillus rhamnosus LGG on the composition and function of the intestinal microbiome

Authors: Solano-Aguilar, Gloria; Lakshman, Sukla; Jang, Saebyeol; Beshah, Ethiopia; XIE, YUE - Sichuan University; SIKAROODI, MASOUMEH - George Mason University; GUPTA, RICHI - George Mason University; Vinyard, Bryan; Molokin, Aleksey; Urban, Joseph; GILLEVET, PATRICK - George Mason University; DAVIS, CINDY - National Institutes Of Health (NIH)

Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2018
Publication Date: 5/1/2018
Citation: Solano Aguilar, G., Lakshman, S., Jang, S., Beshah, E., Xie, Y., Sikaroodi, M., Gupta, R., Vinyard, B.T., Molokin, A., Urban Jr, J.F., Gillevet, P., Davis, C. 2018. The effect of feeding cocoa powder and Lactobacillus rhamnosus LGG on the composition and function of the intestinal microbiome. Current Developments in Nutrition. (2)5. https://doi.org/10.1093/cdn/nzy011.
DOI: https://doi.org/10.1093/cdn/nzy011

Interpretive Summary: Diet can induce changes in the composition and function of microbiota and play a role in the regulation of intestinal gut function. Thirty two pigs were prospectively enrolled in a 4-week dietary intervention study to compare the effect of different diets supplemented with flavanol enriched cocoa powder, probiotic Lactobacillus rhamnossus LGG, or the combination of cocoa powder + LGG relative to a dietary matched control group supplemented with matching amount of fiber and maltodextrin. Fecal samples of pigs from each dietary group (n=8) were collected before the beginning of the experiment and four weeks after dietary intervention. We characterized the fecal microbiota of each dietary group by PCR amplification of the first two variable regions of the 16S rRNA gene and then amplify the community with tagged fusion primers for multitag pyrosequencing. Differences in relative abundance of bacteria at the phylum level indicated an increase in the Bacteroidetes:Firmicutes (B:F) phylum ratio, due to an increased- Bacteroidetes abundance following dietary supplementation with either fiber, cocoa powder or cocoa powder + LGG relative to baseline pre-treatment levels (p<0.05, wilcoxon signed rank test). Prediction of function was done using taxonomic information derived from 16S rRNA gene for each sample using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analytical platform and the effect size of each differentially abundant trait was estimated by Linear discriminant analysis (LDA) effect size (LEfSe) with LDA >3.0. Predicted data indicated a diet effect on metabolic function distribution as fiber-malto and LGG-cocoa derived microbiomes induced a more diverse metabolic function profile as opposed to a predominant energy and Carbohydrate metabolism in Cocoa and probiotic LGG derived microbiomes respectively. Taken together our study indicated that dietary supplementation with fiber, cocoa and the combination of cocoa with LGG probiotic but not LGG alone affect fecal microbiota composition with an enriched energy metabolism for cocoa and a more diverse metabolic profile when LGG is combined with cocoa. This study provides evidence for a modulatory effect of dietary cocoa on host microbiota composition and intestinal bacterial function.

Technical Abstract: Diet-induced changes in the gut microbiome play a prominent role in the regulation of intestinal function. Four groups of eight pigs each were fed a corn-, alfalfa-, and soy-based diet that was supplemented with 1) cocoa powder, 2) probiotic Lactobacillus rhamnossus LGG, 3) a combination of cocoa powder + LGG or 4) fiber-maltodextrin as a vehicle-matched control group. Fecal samples from pigs in each treatment group were collected at weeks 0 (baseline) and four weeks after initiation of dietary intervention. We characterized the fecal associated microbiota by PCR amplification of the first two variable regions of the 16S rRNA gene and then amplified the community with tagged fusion primers for multi-tag sequencing. Differences in relative abundance of bacterial taxa showed an increase in the Bacteroidetes:Firmicutes (B:F) phyla ratio, due to a relative increase in Bacteroidetes abundance in pigs fed the fiber-maltodextrin control diet, cocoa powder or cocoa powder + LGG relative to baseline pre-treatment levels (p<0.05, Wilcoxon signed rank test) with an increased Shannon diversity index in the cocoa-powder + LGG group only (P<0.05). Predictions of metagenomic function from phylogenetic profiles were calculated using 16S rRNA sequence data for each sample through Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) and the relative effect of each trait was estimated by Linear discriminant analysis (LDA) and effect size (LEfSe). Pigs fed fiber-maltodextrin or cocoa powder + LGG expressed a more diverse metabolic profile compared to pigs fed either cocoa powder or LGG alone. The study indicated that a corn-, alfalfa-, and soy-based diet supplemented with fiber-maltodextrin, cocoa powder, or cocoa powder + LGG but not LGG alone altered the composition of the fecal microbiome. Predicted microbiome-related metabolic profiles were more diverse in pigs treated with cocoa powder + LGG. This study provides evidence for a modulatory effect of diets supplemented with cocoa on the composition of the host microbiome and intestinal bacterial function.