title: Association of obesity with serum leptin, adiponectin, and serotonin and gut microflora in beagle dogs.
abstract: BACKGROUND
  Serotonin (5-hydroxytryptamine, 5HT) is involved in hypothalamic regulation of energy consumption. Also, the gut microbiome can influence neuronal signaling to the brain through vagal afferent neurons. Therefore, serotonin concentrations in the central nervous system and the composition of the microbiota can be related to obesity.
  
  
  OBJECTIVE
  To examine adipokine, and, serotonin concentrations, and the gut microbiota in lean dogs and dogs with experimentally induced obesity.
  
  
  METHODS
  Fourteen healthy Beagle dogs were used in this study.
  
  
  METHODS
  Seven Beagle dogs in the obese group were fed commercial food ad libitum, over a period of 6 months to increase their weight and seven Beagle dogs in lean group were fed a restricted amount of the same diet to maintain optimal body condition over a period of 6 months. Peripheral leptin, adiponectin, 5HT, and cerebrospinal fluid (CSF-5HT) levels were measured by ELISA. Fecal samples were collected in lean and obese groups 6 months after obesity was induced. Targeted pyrosequencing of the 16S rRNA gene was performed using a Genome Sequencer FLX plus system.
  
  
  RESULTS
  Leptin concentrations were higher in the obese group (1.98 ± 1.00) compared to those of the lean group (1.12 ± 0.07, P = .025). Adiponectin and 5-hydroytryptamine of cerebrospinal fluid (CSF-5HT) concentrations were higher in the lean group (27.1 ± 7.28) than in the obese group (14.4 ± 5.40, P = .018). Analysis of the microbiome revealed that the diversity of the microbial community was lower in the obese group. Microbes from the phylum Firmicutes (85%) were predominant group in the gut microbiota of lean dogs. However, bacteria from the phylum Proteobacteria (76%) were the predominant group in the gut microbiota of dogs in the obese group.
  
  
  CONCLUSIONS
  Decreased 5HT levels in obese group might increase the risk of obesity because of increased appetite. Microflora enriched with gram-negative might be related with chronic inflammation status in obese dogs.
authors.affiliation: Laboratory of Veterinary Internal Medicine, College of Veterinary Medicine, Chungnam National University, Daejeon, South Korea.
authors.forename: H-J
authors.initials: HJ
authors.lastname: Park
authors.forename: S-E
authors.initials: SE
authors.lastname: Lee
authors.forename: H-B
authors.initials: HB
authors.lastname: Kim
authors.forename: R E
authors.initials: RE
authors.lastname: Isaacson
authors.forename: K-W
authors.initials: KW
authors.lastname: Seo
authors.forename: K-H
authors.initials: KH
authors.lastname: Song
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000818:Animals; D004283:Dog Diseases / Q000097:blood* / Q000134:cerebrospinal fluid / Q000382:microbiology; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000382:microbiology*; D020738:Leptin / Q000097:blood*; D009765:Obesity / Q000097:blood / Q000134:cerebrospinal fluid / Q000382:microbiology / Q000662:veterinary*; D012701:Serotonin / Q000097:blood*
chemical_list: D052242:Adiponectin; D020738:Leptin; D012701:Serotonin
keywords: Adipokine; Dog; Microbiome; Microbiota; Nutrition; Obesity; Pyrosequencing; Serotonin