Acclimation of intestinal morphology and function in djungarian hamsters (Phodopus sungorus) related to seasonal and acute energy balance

Abstract

Small mammals exhibit seasonal changes in intestinal morphology and function via increased intestine size and resorptive surface and/or nutrient transport capacity to increase energy yield from food during winter. This study investigated whether seasonal or acute acclimation to anticipated or actual energetic challenges in Djungarian hamsters also resulted in higher nutrient resorption capacities due to changes in small intestine histology and physiology. The hamsters show numerous seasonal energy saving adjustments in response to short photoperiod. As spontaneous daily torpor represents one of these adjustments related to food quality and quantity, it was hypothesized that the hamsters’ variable torpor expression patterns are influenced by their individual nutrient uptake capacity. Hamsters under short photoperiod showed longer small intestines and higher mucosal electrogenic transport capacities for glucose relative to body mass. Similar observations were made in hamsters under long photoperiod and food restriction. However, this acute energetic challenge caused a stronger increase of glucose transport capacity. Apart from that, neither fasting-induced torpor in food-restricted hamsters nor spontaneous daily torpor in short photoperiod-exposed hamsters clearly correlated with mucosal glucose transport capacity.Both seasonally anticipated and acute energetic challenges caused adjustments in the hamsters’ small intestine. Short photoperiod appeared to induce an integration of these and other acclimation processes in relation to body mass to achieve a long-term adjustment of energy balance. Food restriction seemed to result in a more flexible, short-term strategy of maximizing energy uptake possibly via mucosal glucose transport and reducing energy consumption via torpor expression as emergency response.

Body Temperature and Activity Adaptation of Short Photoperiod-Exposed Djungarian Hamsters (Phodopus sungorus): Timing, Traits, and Torpor

“…Data on relative body mass reduction and relative torpor incidence of 10 hamsters (2018 breed) have already been published in another research context ( Piscitiello et al, 2021 ), while studies on molecular analyses of the hamsters’ tissues are in progress. Therefore, the radiotelemetry data of this study are not yet published for free use, but can be provided on request.…”

Seasonal and fasting induced changes in iron metabolism in Djungarian hamsters

“…We next questioned whether food restriction, hence forced body weight reduction, affects iron metabolism to similar extent as voluntary seasonal body weight reduction. To this end, we used a previously established regime where hamsters were subjected to 5 weeks of moderate food restriction ( Fig 1 ) [ 11 ].…”

“…An index of 1 accounted for grey-brown summer fur and 6 for a white, well-insulating winter fur. After 10–12 weeks in SP, all hamsters were intraperitoneally implanted with telemetric transmitters (TA11TA-F10, Data Science International, St Paul, MN, USA; silicone-coated, 1.1 cc volume, 1.6 g weight, 0.15°C accuracy) to continuously measure body temperature as thus to record spontaneous daily torpor bouts ( Fig 1 ) (for details see [ 3 , 11 ]). The surgery was carried out under carprofen analgesia (5mg/kg; Rimadyl®, Zoetis Deutschland GmbH, Berlin) and isoflurane anaesthesia (2.5% induction, 0.75–2.0% maintenance; Forene® Abbvie, Ludwigshafen, Germany).…”

“…Reduced food intake and consequent reduction of body weight seem to play a significant role in the initiation and manifestation of torpor [ 10 ]. This becomes evident from the studies showing that daily torpor episodes can be triggered by long-term food restriction paradigms in long photoperiod [ 10 , 11 , 12 ].…”

Short Photoperiod-Dependent Enrichment of Akkermansia spec. as the Major Change in the Intestinal Microbiome of Djungarian Hamsters (Phodopus sungorus)

“…The energy-saving purpose of these changes is undeniable, and the hamsters achieve it by decreasing energy expenditure, as well as increasing energy assimilation from a given amount of food. Piscitiello and coworkers showed that the small intestine of short photoperiod-acclimated hamsters had a relatively larger mucosal surface and electrogenic glucose transport capacity compared to hamsters in a long summer-like photoperiod, presumably resulting in a body size-optimized glucose uptake capacity [ 10 ]. Regarding glucose as the major energy source, a much earlier study in mice already demonstrated that the microbiome profile also influences the intestinal energy assimilation capacity by changing glucose absorption [ 11 ].…”