Dietary protein sources differentially affect microbiota, mTOR activity and transcription of mTOR signaling pathways in the small intestine

Abstract

Dietary protein sources can have profound effects on host-microbe interactions in the gut that are critically important for immune resilience. However more knowledge is needed to assess the impact of different protein sources on gut and animal health. Thirty-six wildtype male C57BL/6J mice of 35 d age (n = 6/group; mean ± SEM body weight 21.9 ± 0.25 g) were randomly assigned to groups fed for four weeks with semi synthetic diets prepared with one of the following protein sources containing (300 g/kg as fed basis): soybean meal (SBM), casein, partially delactosed whey powder, spray dried plasma protein, wheat gluten meal and yellow meal worm. At the end of the experiment, mice were sacrificed to collect ileal tissue to acquire gene expression data, and mammalian (mechanistic) target of rapamycin (mTOR) activity, ileal digesta to study changes in microbiota and serum to measure cytokines and chemokines. By genome-wide transcriptome analysis, we identified fourteen high level regulatory genes that are strongly affected in SBM-fed mice compared to the other experimental groups. They mostly related to the mTOR pathway. In addition, an increased (P < 0.05) concentration of granulocyte colony-stimulating factor was observed in serum of SBM-fed mice compared to other dietary groups. Moreover, by 16S rRNA sequencing, we observed that SBM-fed mice had higher (P < 0.05) abundances of Bacteroidales family S24-7, compared to the other dietary groups. We showed that measurements of genome-wide expression and microbiota composition in the mouse ileum reveal divergent responses to diets containing different protein sources, in particular for a diet based on SBM.

Dietary Protein and Muscle in Aging People: The Potential Role of the Gut Microbiome

“…Studies carried out in mice, rats, and hamsters have shown higher microbial diversity in those fed soy protein versus animal protein [ 133 , 134 ] and increased abundance of Bacteroidales family S24-7 in those fed soy protein versus other diets [ 79 ]. Li et al (2017) assessed high protein, low carbohydrate diets in dogs and found decreased Bacteroidetes to Firmicutes ratio, increased Bacteroides to Prevotella ratio and increased abundance of Clostridium hiranonis , Clostridium perfringens , and Ruminococcus gnavus , the latter of which has been proposed to have beneficial effects in the human gut [ 135 ].…”

Dietary L-Tryptophan Modulates the Structural and Functional Composition of the Intestinal Microbiome in Weaned Piglets

“…Dietary protein intake can alter the gut microbiota, thus contributing to structural and functional changes of the host intestine ( David et al, 2014 ; Beaumont et al, 2017 ; Kar et al, 2017 ; Llewellyn et al, 2017 ; Tilocca et al, 2017 ). However, there is a scarcity of information regarding impacts of specific amino acids on the gut flora composition and intestinal health in animals.…”

Dietary Cows’ Milk Protein A1 Beta-Casein Increases the Incidence of T1D in NOD Mice

“…Despite the limitations described above, we propose that A1 beta-casein influences T1D incidence through a number of potential mechanisms mediated via BCM-7. We hypothesise that BCM-7 released from A1 beta-casein may influence the immune response [ 38 ], gut architecture and microbiota [ 71 , 72 , 78 ] and/or impart direct islet toxicity. Together, these effects may induce epigenetic alterations predisposing pancreatic beta-cells to an autoimmune response ( Figure 4 ) [ 60 , 79 ].…”