Fig. 1.

Indirect open-circuit calorimetry in gnotobiotic isolators. a Schematic drawing of the experimental apparatus. Two isolators are shown: isolator A contains animals colonized with bacterial consortium A from the lean co-twin; isolator B contains animals harboring bacterial consortium B from the obese co-twin. b Photograph of flexible film gnotobiotic isolator containing a metabolic chamber and devices used to connect the chamber to the exterior calorimeter