Department of Pharmacology and Toxicology, School of Medicine, Wright State University, Dayton, OH, United States of America.
PLoS One. 2021 Feb 4;16(2):e0246569. doi: 10.1371/journal.pone.0246569. eCollection 2021.
The feeding pattern and control of energy intake in mice housed in groups are poorly understood. Here, we determined and quantified the normal feeding microstructure of social male and female mice of the C57BL/6J genetic background fed a chow diet. Mice at 10w, 20w and 30w of age showed the expected increase in lean and fat mass, being the latter more pronounced and variable in males than in females. Under ad libitum conditions, 20w and 30w old females housed in groups showed significantly increased daily energy intake when adjusted to body weight relative to age-matched males. This was the combined result of small increases in energy intake during the nocturnal and diurnal photoperiods of the day without major changes in the circadian pattern of energy intake or spontaneous ambulatory activity. The analysis of the feeding microstructure suggests sex- and age-related contributions of meal size, meal frequency and intermeal interval to the control of energy intake under stable energy balance, but not under negative energy balance imposed by prolonged fasting. During the night, 10-20w old females ate less frequently bigger meals and spent more time eating them resulting in reduced net energy intake relative to age-matched males. In addition, male and female mice at all ages tested significantly shortened the intermeal interval during the first hours of re-feeding in response to fasting without affecting meal size. Further, 20-30w old males lengthened their intermeal interval as re-feeding time increased to reach fed-levels faster than age-matched females. Collectively, our results suggest that the physiological mechanisms controlling meal size (satiation) and the non-eating time spent between meals (satiety) during stable or negative energy balance are regulated in a sex- and age-dependent manner in social mice.
群体饲养的小鼠的进食模式和能量摄入控制了解甚少。在这里，我们确定并量化了 C57BL/6J 遗传背景下社交雄性和雌性小鼠的正常进食微观结构，这些小鼠喂食标准饮食。10 周、20 周和 30 周龄的小鼠表现出瘦体重和脂肪量的预期增加，后者在雄性中比在雌性中更为明显和多变。在自由进食条件下，与年龄匹配的雄性相比，20 周和 30 周龄的群居雌性小鼠的每日能量摄入量相对体重显著增加。这是由于白天的夜间和白天光周期内能量摄入略有增加，而能量摄入的昼夜节律或自发活动没有发生重大变化所致。进食微观结构的分析表明，在稳定的能量平衡下，性别和年龄相关的餐量、进餐频率和两餐之间的间隔对能量摄入的控制有贡献，但在延长禁食引起的负能量平衡下则没有。在夜间，10-20 周龄的雌性小鼠进食频率较低，餐量较大，进食时间较长，导致与年龄匹配的雄性相比净能量摄入减少。此外，所有测试年龄的雄性和雌性小鼠在禁食后，为响应重新进食，显著缩短了两餐之间的间隔，而不影响餐量。此外，20-30 周龄的雄性小鼠随着重新进食时间的增加而延长两餐之间的间隔，以比年龄匹配的雌性更快地达到进食水平。总之，我们的研究结果表明，在稳定或负能量平衡下控制餐量（饱腹感）和两餐之间非进食时间（满足感）的生理机制在社交小鼠中以性别和年龄依赖的方式进行调节。
