Altered circadian rhythms have negative consequences on health and behavior. Emerging evidence suggests genetics influences the physiological and behavioral responses to circadian disruption. We investigated the effects of a 21 h day (T = 21 cycle), with high-fat diet consumption, on locomotor activity, explorative behaviors, and health in male C57BL/6J and C57BL/6N mice. Mice were exposed to either a T = 24 or T = 21 cycle and given standard rodent chow (RC) or a 60% high-fat diet (HFD) followed by behavioral assays and physiological measures. We uncovered numerous strain differences within the behavioral and physiological assays, mainly that C57BL/6J mice exhibit reduced susceptibility to the obesogenic effects of (HFD) and anxiety-like behavior as well as increased circadian and novelty-induced locomotor activity compared to C57BL/6N mice. There were also substrain-specific differences in behavioral responses to the T = 21 cycle, including exploratory behaviors and circadian locomotor activity. Under the 21-h day, mice consuming RC displayed entrainment, while mice exposed to HFD exhibited a lengthening of activity rhythms. In the open-field and light-dark box, mice exposed to the T = 21 cycle had increased novelty-induced locomotor activity with no further effects of diet, suggesting daylength may affect mood-related behaviors. These results indicate that different circadian cycles impact metabolic and behavioral responses depending on genetic background, and despite circadian entrainment.

昼夜节律改变会对健康和行为产生负面影响。越来越多的证据表明，遗传学影响着对生物钟破坏的生理和行为反应。我们调查了高脂饮食对21 h一天（T = 21周期）的影响对雄性C57BL / 6J和C57BL / 6N小鼠运动能力，探索行为和健康的影响。将小鼠暴露于T ＝ 24或T ＝ 21周期，并给予标准啮齿动物食物（RC）或60％高脂饮食（HFD），随后进行行为测定和生理学测量。我们在行为和生理测定中发现了许多菌株差异，主要是与C57BL / 6N相比，C57BL / 6J小鼠对（HFD）致肥胖作用和焦虑样行为的敏感性降低，并且昼夜节律和新奇诱导的自发活动老鼠。T = 21周期的行为反应也存在亚种特异性差异，包括探索行为和昼夜运动能力。在21小时内，食用RC的小鼠表现出夹带作用，而暴露于HFD的小鼠表现出活动节律延长。在开放视野和明暗盒子中，暴露于T = 21周期的小鼠具有新奇诱导的运动能力增强，而饮食没有进一步的影响，这表明日长可能会影响与情绪相关的行为。这些结果表明，尽管有昼夜节律，但不同的昼夜节律周期仍会影响代谢和行为反应，具体取决于遗传背景。食用RC的小鼠表现出夹带，而暴露于HFD的小鼠表现出活动节律的延长。在开放视野和明暗盒子中，暴露于T = 21周期的小鼠具有新奇诱导的运动能力增强，而饮食没有进一步的影响，这表明日长可能会影响与情绪相关的行为。这些结果表明，尽管有昼夜节律，但不同的昼夜节律周期仍会影响代谢和行为反应，具体取决于遗传背景。食用RC的小鼠表现出夹带，而暴露于HFD的小鼠表现出活动节律的延长。在开放视野和明暗盒子中，暴露于T = 21周期的小鼠具有新奇诱导的运动能力增强，而饮食没有进一步的影响，这表明日长可能会影响与情绪相关的行为。这些结果表明，尽管有昼夜节律，但不同的昼夜节律周期仍会影响遗传和行为反应，具体取决于遗传背景。