title: Relationships between diet-related changes in the gut microbiome and cognitive flexibility.
abstract: Western diets are high in fat and sucrose and can influence behavior and gut microbiota. There is growing evidence that altering the microbiome can influence the brain and behavior. This study was designed to determine whether diet-induced changes in the gut microbiota could contribute to alterations in anxiety, memory or cognitive flexibility. Two-month-old, male C57BL/6 mice were randomly assigned high-fat (42% fat, 43% carbohydrate (CHO), high-sucrose (12% fat, 70% CHO (primarily sucrose) or normal chow (13% kcal fat, 62% CHO) diets. Fecal microbiome analysis, step-down latency, novel object and novel location tasks were performed prior to and 2weeks after diet change. Water maze testing for long- and short-term memory and cognitive flexibility was conducted during weeks 5-6 post-diet change. Some similarities in alterations in the microbiome were seen in both the high-fat and high-sucrose diets (e.g., increased Clostridiales), as compared to the normal diet, but the percentage decreases in Bacteroidales were greater in the high-sucrose diet mice. Lactobacillales was only significantly increased in the high-sucrose diet group and Erysipelotrichales was only significantly affected by the high-fat diet. The high-sucrose diet group was significantly impaired in early development of a spatial bias for long-term memory, short-term memory and reversal training, compared to mice on normal diet. An increased focus on the former platform position was seen in both high-sucrose and high-fat groups during the reversal probe trials. There was no significant effect of diet on step-down, exploration or novel recognitions. Higher percentages of Clostridiales and lower expression of Bacteroidales in high-energy diets were related to the poorer cognitive flexibility in the reversal trials. These results suggest that changes in the microbiome may contribute to cognitive changes associated with eating a Western diet.
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 USA; Linus Pauling Institute, Oregon State University, Corvallis, OR 97331 USA. Electronic address: Kathy.Magnusson@oregonstate.edu.
authors.forename: K R
authors.initials: KR
authors.lastname: Magnusson
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 USA. Electronic address: LauraLHauck@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Hauck
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 USA. Electronic address: jeffrebr@onid.orst.edu.
authors.forename: B M
authors.initials: BM
authors.lastname: Jeffrey
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 USA; Linus Pauling Institute, Oregon State University, Corvallis, OR 97331 USA. Electronic address: Valerie.Elias@oregonstate.edu.
authors.forename: V
authors.initials: V
authors.lastname: Elias
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 USA. Electronic address: a.humphrey7@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Humphrey
authors.affiliation: Department of Human Development and Family Sciences, School of Social and Behavioral Health Sciences, Oregon State University, Corvallis, OR 97331 USA. Electronic address: rngero2010@gmail.com.
authors.forename: R
authors.initials: R
authors.lastname: Nath
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 USA; Linus Pauling Institute, Oregon State University, Corvallis, OR 97331 USA. Electronic address: perronea@onid.orst.edu.
authors.forename: A
authors.initials: A
authors.lastname: Perrone
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331 USA. Electronic address: Luiz.Bermudez@oregonstate.edu.
authors.forename: L E
authors.initials: LE
authors.lastname: Bermudez
mesh_terms: D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D003071:Cognition / Q000502:physiology*; D059305:Diet, High-Fat / Q000009:adverse effects*; D019422:Dietary Sucrose / Q000009:adverse effects*; D004435:Eating; D056344:Executive Function / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology; D005243:Feces / Q000382:microbiology; D000069196:Gastrointestinal Microbiome / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology; D057567:Memory, Long-Term / Q000502:physiology; D008570:Memory, Short-Term / Q000502:physiology; D008810:Mice, Inbred C57BL; D009483:Neuropsychological Tests; D011897:Random Allocation; D021641:Recognition, Psychology / Q000502:physiology; D012193:Reversal Learning / Q000502:physiology; D065852:Spatial Memory / Q000502:physiology
chemical_list: D019422:Dietary Sucrose
keywords: Bacteroidales; Clostridiales; Western diet; executive function; intestinal microbiota; sucrose