Cold exposure impairs the muscle growth-promoting effect of nighttime-restricted feeding by desynchronizing mitochondrial energy supply rhythm in rabbits.

Feeding time and ambient temperature are critical zeitgebers that modulate both biological rhythms and muscle nutrient partitioning in animals. While time-restricted feeding can improve peripheral circadian rhythms and enhance glucose and lipid metabolism, its interaction with cold exposure and the resultant impact on muscle growth remain unclear. Using rabbits as an experimental model, this study demonstrates that under optimal temperatures, feeding promotes growth by sustaining mitochondrial energy rhythms via clock genes. In contrast, cold exposure induces hypothermia, elevating glucocorticoids and activating the skeletal muscle TRPM8/HSF1 pathway, which dysregulates muscle clock gene rhythms. This cascade ultimately impairs mitochondrial function, suppresses cell cycle gene expression, and collectively contributes to hindered muscle growth. This research provides a theoretical basis for developing improved livestock raising practices and offers insights into the regulation of muscle metabolism in humans under complex environmental conditions.