Host-microbiota interactions play a central role in how animals adjust to changing environments, including fluctuations in energy availability. The extent to which hosts and their gut microbial communities exhibit coordinated, reversible plasticity in response to transient energy restriction is not well established. This study tested whether selection for high aerobic metabolism alters the capacity for parallel, reversible responses in host physiology and gut microbiota composition when animals encounter temporary dietary restriction.
The experiment used bank voles (Clethrionomys glareolus) derived from a long-term artificial selection program. Two types of selection lines were included: lines selected for high aerobic metabolism (A-lines) and unselected control lines (C-lines). Voles from both line types were sampled at three time points: baseline (pre-restriction), after a period of dietary restriction, and after a recovery period following restoration of the original diet.
Dietary restriction was imposed by diluting the regular diet with insoluble fiber. The reduction in available dietary energy was therefore achieved without complete fasting but by lowering energy density. Fecal samples and physiological measurements were collected at baseline, immediately after the dietary restriction period, and after a recovery interval in which the standard diet was resumed.
The study measured traits relevant to energy balance: food consumption, body mass, and resting metabolic rate (RMR). Across both selection lines, dietary restriction produced a temporary increase in food consumption, consistent with compensatory intake responses to lower dietary energy density. Body mass and RMR decreased during the restriction period. Importantly, these physiological effects largely returned toward baseline values during the recovery period, indicating reversible host physiological plasticity in response to the transient energy limitation.
Fecal microbiota composition was characterized at each sampling point to assess community-level responses to dietary restriction and subsequent recovery. Dietary restriction induced significant shifts in gut microbiota composition, demonstrating that transient changes in dietary energy availability alter microbial community structure. Like the measured physiological traits, the microbiota composition tended to return near baseline after the recovery period, indicating reversible microbiota plasticity under the experimental conditions.
Although the authors hypothesized that voles from A-lines (selected for higher aerobic metabolism) would experience more severe or prolonged physiological effects of dietary restriction and might rely on greater microbiota responsiveness to compensate, the observed patterns were different. Physiological responses to dietary restriction (increased food intake, decreased body mass and RMR, and recovery toward baseline) were largely similar between A-line and C-line voles.
A notable divergence emerged for microbial diversity: the effect of dietary restriction on bacterial diversity was stronger in the C-lines than in the A-lines. In other words, the gut microbiota of A-line voles showed a reduced responsiveness in diversity metrics to the dietary manipulation compared with control voles.
The authors interpret the comparatively muted microbiota response in A-line voles as evidence for increased resistance of the A-line microbiota to dietary perturbation. They propose that directional selection for high metabolic capacity in hosts may enhance host regulatory control over gut microbial communities, leading to reduced microbial responsiveness to short-term changes in diet. This interpretation aligns with the observation that A-line physiology did not exhibit exaggerated or prolonged adverse effects relative to controls, despite the selection history.
This study demonstrates substantial reversible plasticity in both host physiological traits and gut microbiota composition in bank voles subjected to transient dietary restriction. Selection for high aerobic metabolism was associated with reduced microbiota responsiveness in terms of bacterial diversity, suggesting that evolutionary changes in host energetics can modulate host–microbiota dynamics. These results highlight that host selection history can influence how microbiota respond to environmental stressors such as temporary reductions in dietary energy. Details on specific taxa-level changes, statistical values, sample sizes, and timelines were reported in the original article but are not detailed here in the source summary.