Early life diet alters sleep architecture following an acute stress: The potential role of milk oligosaccharides

Abstract

Stress exposure can produce disruptions in the sleep cycle that may contribute to altered cognitive performance. Prebiotics can selectively enhance select gut microbial species that may promote favorable response to stressrobustness. Our previous studies showed that a milk oligosaccharide, sialyllactose, supported normal microbial communities (similar to non‐stressed animals) and behavioral responses during stressor exposure, potentially through effects on the gut microbiota–brain axis. The aim of the current study was to determine whether early life dietary oligosaccharides would modulate the sleep cycle and protect sleep architecture following stress. We hypothesized that diet containing a blend of prebiotics (galactooligosaccharides, GOS+polydextrose, PDX) and/or sialyllactose (Lacprodan SAL‐10®; SL) would mitigate stress induced alterations of electrophysiological markers of sleep. Male Sprague Dawley rats (postnatal day (P)21) were placed on one of the experimental diets for 30d: a) SL [2.2g/kg], b)GOS+PDX [7g/kg each], c) GOS+PDX [7g/kg each] + SL [2.2g/kg] or d) Control[cellulose as fiber source]. Telemetry devices were implanted on P64 to examine the differences in electroencephalograph (EEG) and electromyograph (EMG)measurements. Baseline 24h EEG recordings were performed on P84. Rats were exposed to an acute stressor (inescapable stress) on P85 in order to examine the potential protective effects of our experimental diets on stress‐induced sleep/wake cycle. An additional group of Control animals remained undisturbed(Control Unstressed). There were no differences in food intake and body weight gain among the groups. There was a normal EEG distribution of power across the 24 h period under baseline conditions for all diets. During baseline, GOS+PDX+SL group had decreased waketheta frequency compared to Control Unstressed group (P<0.05). All stressed groups slept more (both NREM and REM) compared to the Control Unstressed group. Test diet groups had less overall waking following stress compared to the control animals. Rats on GOS+PDX diet had more overall NREM (NREM consolidation)compared to Control Unstressed animals (P<0.05). REM alpha and beta power were increased in rats on GOS+PDX and SL diets compared to control animals during baseline (prior to stress exposure) and following stress (P<0.05). Overall, these data demonstrate that an early life diet containing GOS+PDX and/or SL can increase NREM sleep consolidation and mitigate stress‐induced sleep disruptions in adulthood. Ongoing microbiome analysis might provide further insights on the mechanism of actions of this novel dietary intervention.Support or Funding InformationSupported by Mead Johnson Nutrition.