Microbiota Regulate Intestinal Absorption and Metabolism of Fatty Acids in the Zebrafish

Abstract

SUMMARY Regulation of intestinal dietary fat absorption is critical to maintaining energy balance. While intestinal microbiota clearly impact the host’s energy balance, their role in intestinal absorption and extra-intestinal metabolism of dietary fat is less clear. Using in vivo imaging of fluorescent fatty acid (FA) analogs delivered to gnotobiotic zebrafish hosts, we reveal that microbiota stimulate FA uptake and lipid droplet (LD) formation in the intestinal epithelium and liver. Microbiota increase epithelial LD number in a diet-dependent manner. The presence of food led to the intestinal enrichment of bacteria from the phylum Firmicutes. Diet-enriched Firmicutes and their products were sufficient to increase epithelial LD number, whereas LD size was increased by other bacterial types. Thus, different members of the intestinal microbiota promote FA absorption via distinct mechanisms. Diet-induced alterations in microbiota composition might influence fat absorption, providing mechanistic insight into how microbiota-diet interactions regulate host energy balance.

Water fleas require microbiota for survival, growth and reproduction

“…Hence, the symptoms we observed in microbiota-free D. magna could be attributed to reduced food intake or energy uptake or both. This suggestion is consistent with observations of reduced fat reserves in microbiota-free mice and zebrafish (Bäckhed et al, 2004;Semova et al, 2012) and to findings from abalone and sturgeons relating the presence of different bacteria to enhanced digestive enzyme activities (Askarian et al, 2011;Zhao et al, 2012). Although D. magna has digestive enzymes used for breaking down food such as proteases, amylases and lipases (Hasler, 1935;von Elert et al, 2004), the contribution of gut microbiota to these functions is unknown.…”

Polygala tenuifolia extract inhibits lipid accumulation in 3T3-L1 adipocytes and high-fat diet–induced obese mouse model and affects hepatic transcriptome and gut microbiota profiles

“…These findings support the mechanism that obesity development is highly correlated with low-grade chronic inflammation and gut microbiota alteration. A HFD was shown to increase the Firmicutes population, which strengthens lipid droplet formation and absorption [63]. Additionally, a HFD causes a decrease in the Bacteroidetes population.…”

Divergence across diet, time and populations rules out parallel evolution in the gut microbiomes of Trinidadian guppies

“…Dietary differences have also been observed in commongarden settings (Bassar et al, 2010) and appear related to differences in gut morphology and physiology (Sullam et al, 2014). Combined with known roles for microbial symbionts in dietary utilization and processing (Semova et al, 2012), this raises the expectation that HP and LP guppies may have undergone parallel changes in their gut microbiomes should bacterial shifts be integral to shifts in host diet. Such microbiome divergence could also occur if diet has a strong, proximate impact upon gut communities.…”

“…Bacteria play a fundamental role in animal biology, and recent work has revolutionized our understanding of how these ubiquitous organisms affect their hosts' development, physiology, ecology and evolution (Zilber-Rosenberg and Rosenberg, 2008;Lee and Mazmanian, 2010;Semova et al, 2012;Tremaroli and Backhed, 2012;McFall-Ngai et al, 2013). Across mammalian species, host phylogeny and diet correlate with the structure and diversity of gut bacterial communities (Ley et al, 2008).…”