Association of Obesity with Serum Leptin, Adiponectin, and Serotonin and Gut Microflora in Beagle Dogs

Abstract

BackgroundSerotonin (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.ObjectiveTo examine adipokine, and, serotonin concentrations, and the gut microbiota in lean dogs and dogs with experimentally induced obesity.AnimalsFourteen healthy Beagle dogs were used in this study.MethodsSeven 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.ResultsLeptin 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 and Clinical ImportanceDecreased 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.

Akkermansia and Microbial Degradation of Mucus in Cats and Dogs: Implications to the Growing Worldwide Epidemic of Pet Obesity

“…Obesity is a growing problem in cats and dogs and several lines of research point out a potential role of the gut microbiota in this disorder [189][190][191][192][193]; therefore, several efforts have been directed to help these patients but mostly centered around dietary therapies [3]. A. muciniphila is currently considered a beneficial microbe that could help in the treatment of obesity, diabetes, and associated disorders in humans when administered orally, either alive or even pasteurized [56,194,195].…”

Functional Pet Foods

“…Therefore, it is reasonable to think that future dietary products for dogs will modulate the gut microbial population in order to treat or prevent some food-related diseases (dysbiosis, leaky gut, intestinal bowel disease, irritable bowel syndrome, coeliac disease, sepsis, renal failure, autoimmune disease, peritonitis, and intestinal obstruction). Recently, Park and coworkers monitored healthy dogs for 6 months [110]. The first group was fed ad libitum on commercial food, while the second was fed on a restricted amount of the same commercial food.…”

Role of Gut Microbiota in Neuroendocrine Regulation of Carbohydrate and Lipid Metabolism via the Microbiota-Gut-Brain-Liver Axis

“…When vagal afferent neurons sense these types of gut peptides, the corresponding gut information will transfer to the CNS and exert various reactions. At the same time, gut microbiota can regulate these gut peptides, such as CCK, ghrelin, leptin, PYY, GLP-1, 5-HT levels to influence vagal afferent pathway, and then regulated intestinal metabolic metabolism via the microbiota-gut-brain axis [23][24][25].The importance of the gut-brain axis in human health and disease has been known for a long period. However, it has only been recently recognized that the intestinal microbiota are key regulators of crosstalk between the brain and the gastrointestinal tract to maintain metabolic homeostasis, which is called the microbiota-gut-brain axis [26][27][28].…”

“…The bidirectional communication that occurs for the microbiota-gut-brain axis includes "bottom-up" (from gut microbiota to brain) and "top-down" (from brain to gut microbiota) [29,30]. For example, gut microbiota can regulate levels of gut peptides to influence the vagal afferent pathway and regulate intestinal metabolism via the microbiota-gut-brain axis [23][24][25].Several studies have also confirmed that there are various links between the gut and the liver, and that gut microbiota are also involved in intestinal metabolism through the microbiota-gut-liver axis [31,32]. Therefore, this article mainly summarizes the role of the gut microbiota in neuroendocrine regulation of carbohydrates, lipids, and amino acids via the microbiota-gut-brain-liver axis.…”