title: Protein quality and the protein to carbohydrate ratio within a high fat diet influences energy balance and the gut microbiota in C57BL/6J mice.
abstract: Macronutrient quality and composition are important determinants of energy balance and the gut microbiota. Here, we investigated how changes to protein quality (casein versus whey protein isolate; WPI) and the protein to carbohydrate (P/C) ratio within a high fat diet (HFD) impacts on these parameters. Mice were fed a low fat diet (10% kJ) or a high fat diet (HFD; 45% kJ) for 21 weeks with either casein (20% kJ, HFD) or WPI at 20%, 30% or 40% kJ. In comparison to casein, WPI at a similar energy content normalised energy intake, increased lean mass and caused a trend towards a reduction in fat mass (P = 0.08), but the protein challenge did not alter oxygen consumption or locomotor activity. WPI reduced HFD-induced plasma leptin and liver triacylglycerol, and partially attenuated the reduction in adipose FASN mRNA in HFD-fed mice. High throughput sequence-based analysis of faecal microbial populations revealed microbiota in the HFD-20% WPI group clustering closely with HFD controls, although WPI specifically increased Lactobacillaceae/Lactobacillus and decreased Clostridiaceae/Clostridium in HFD-fed mice. There was no effect of increasing the P/C ratio on energy intake, but the highest ratio reduced HFD-induced weight gain, fat mass and plasma triacylglycerol, non-esterified fatty acids, glucose and leptin levels, while it increased lean mass and oxygen consumption. Similar effects were observed on adipose mRNA expression, where the highest ratio reduced HFD-associated expression of UCP-2, TNFα and CD68 and increased the diet-associated expression of β3-AR, LPL, IR, IRS-1 and GLUT4. The P/C ratio also impacted on gut microbiota, with populations in the 30/40% WPI groups clustering together and away from the 20% WPI group. Taken together, our data show that increasing the P/C ratio has a dramatic effect on energy balance and the composition of gut microbiota, which is distinct from that caused by changes to protein quality.
authors: Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland ; Department of Pharmacology and Therapeutics, University College Cork, Cork, Ireland.
authors: Liam
authors: L
authors: McAllan
authors: Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland ; Department of Microbiology, University College Cork, Cork, Ireland.
authors: Peter
authors: P
authors: Skuse
authors: Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland ; Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland.
authors: Paul D
authors: PD
authors: Cotter
authors: Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland.
authors: Paula
authors: P
authors: O'Connor
authors: Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland ; Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland.
authors: John F
authors: JF
authors: Cryan
authors: Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland.
authors: R Paul
authors: RP
authors: Ross
authors: Department of Microbiology, University College Cork, Cork, Ireland.
authors: Gerald
authors: G
authors: Fitzgerald
authors: UCD Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Dublin, Ireland.
authors: Helen M
authors: HM
authors: Roche
authors: Food Biosciences Department, Teagasc, Fermoy, County Cork, Ireland.
authors: Kanishka N
authors: KN
authors: Nilaweera
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D000596:Amino Acids / Q000097:blood; D000818:Animals; D001823:Body Composition / Q000187:drug effects; D050260:Carbohydrate Metabolism / Q000187:drug effects; D059305:Diet, High-Fat; D004734:Energy Metabolism / Q000187:drug effects; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000382:microbiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006728:Hormones / Q000097:blood; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D064307:Microbiota / Q000187:drug effects; D008894:Milk Proteins / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism*; D000067816:Whey Proteins
chemical_list: D000596:Amino Acids; D006728:Hormones; D008894:Milk Proteins; D011506:Proteins; D000067816:Whey Proteins