Delayed gut colonization changes future insulin resistance and hepatic gene expression but not adiposity in high-fat diet induced obese mice

Since the first findings that germ-free mice appeared resistant to diet-induced obesity, an increasing number of studies have emphasized the role of the gut microbiota as a core regulator of host weight gain and metabolism. However, several studies have not been replicable and conflicting results have left the discussion surrounding causality elusive. Specifically, the importance of early microbial dysbiosis in later development of obesity and metabolic disorders has been a subject of debate. Male Swiss Webster mice raised under germ-free conditions were introduced to a specific-pathogen-free (SPF) facility for microbial colonization at 1 week (1W) and 3 weeks (3W) of age. They were compared with control animals (SPF) with a complete gut microbiota from birth. Liver RNAseq of 7 week old animals showed differential gene expression between the groups