Dietary Bile Salt Types Influence the Composition of Biliary Bile Acids and Gut Microbiota in Grass Carp

Abstract

Lipid metabolism can influence host’s health. There is increasing evidence for interplay between two key regulating factors in lipid metabolism: bile acids (BAs) and gut microbiota. However, very little is known about how types of different diet-supplemented bile salts (BS) influence this interaction in vivo. We sought to explore these relationships using grass carp (Ctenopharyngodon idellus), which often suffers functional disorder of liver and gallbladder. We studied fluctuations of BAs in the gall and changes of microbial communities in the gut in response to seven different diets: five different BS, chelating BS agent, and control. The BS comprised two primary BS [sodium taurochololate (TCAS) and sodium taurochenodeoxycholate (TCDCAS)], sodium tauroursodeoxycholate (TUDCAS), and two secondary BS [sodium taurodeoxycholate (TDCAS) and sodium taurolithocholate (TLCAS)]. Supplementation of primary BS caused a more significant fluctuation of biliary BAs than secondary BS, and TCAS caused a more prominent increase than TCDCAS and TUDCAS. For the gut microbiota, primary BS tended to increase their diversity and induce community succession, secondary BS resulted in a higher firmicutes/bacteroidetes ratio, while TUDCAS had no significant effects. Changes of the gut microbiota triggered by different types of BS caused alteration in BAs biotransformation. Two-obesity-associated families, Lachnospiraceae and Ruminococcaceae were positively correlated with biliary cholic acid (CA), taurochenodeoxycholic acid (TCDCA), and deoxycholic acid (DCA). As both primary and secondary BS resulted in increased synthesis of toxic secondary Bas by the gut microbiota, future studies should pay closer attention to gut microbiota when considering BA treatment.

Hyodeoxycholic acid (HDCA) suppresses intestinal epithelial cell proliferation through FXR‐PI3K/AKT pathway, accompanied by alteration of bile acids metabolism profiles induced by gut bacteria

“…As BA‐metabolizing bacteria, we also found that many of these differential OTUs belonged to Lachnospiraceae and Ruminococcaceae had a strong correlation with altered BAs in feces and serum, indicating that Ruminococcaceae and Lachnospiraceae were closely related to the biotransformation of BAs. Consistent with our findings, a previous study conducted in grass carp feeding different bile salt revealed that Lachnospiraceae and Ruminococcaceae were the bacterial taxa that most closely positively correlated with biliary BAs 51 . In agreement, antibiotics‐induced decrease of secondary BAs (DCA, LCA, UDCA, HDCA, and ω‐MCA) in mice were correlated with the loss of specific microbiota community members, such as the Lachnospiraceae and Ruminococcaceae families 52 .…”

Effects of bile acids on the growth performance, lipid metabolism, non‐specific immunity and intestinal microbiota of Pacific white shrimp ( Litopenaeus vannamei )

“…Our findings indicated that dietary supplementation of bile acids induced marked alterations of functionality of intestinal microbiota in shrimp. Among them, consistent with previous investigations about grass carp (Xiong et al, 2018), the lipid metabolism capacity of intestinal microbiota in BA2 and BA4 groups increased, further confirming that bile acids were significant to the emulsification of lipid and the metabolism of shrimp. Meanwhile, functional genes associated with metabolism (including amino acid, energy, nucleotide, cofactors and vitamins) were all increased after dietary supplementation of bile acids.…”

Effect of Diet Supplemented With Rapeseed Meal or Hydrolysable Tannins on the Growth, Nutrition, and Intestinal Microbiota in Grass Carp (Ctenopharyngodon idellus)

“…The PCR was conducted using the bacterial universal primers 338F (5′ ACT CCT ACG GGA GGC AGC AG 3′) and 806R (5′ GGA CTA CHV GGG TWT CTA AT 3′). The PCR reaction was based on Xiong et al (43). The resulted PCR products were extracted from a 2% agarose gel and further purified using the AxyPrep DNA Gel Extraction Kit (Axygen Biosciences, Union City, CA, USA) and quantified using QuantiFluor™ -ST (Promega, USA) according to the manufacturer's protocol.…”