Mistimed Feeding Disrupts Metabolic Rhythm and Increases Lipid Accumulation of Growing Rabbits in Winter

Maintaining the normal biological rhythms of livestock is of great significance for reflecting the environmental suitability and welfare level of animals. Mistimed feeding can interfere with the circadian rhythms of both humans and animals, resulting in disorders of lipid metabolism, obesity, and metabolic syndrome. Low-temperature environment stimulates increased appetite and decreased physical activity, resulting in higher energy intake than consumption and thus facilitating fat deposition and even obesity. In this study, growing rabbits were randomly allocated to the daytime feeding (DF) group and nighttime restricted feeding (NRF) group. Our research demonstrated that, during winter, the DF regimen disrupted the behavioral rhythms of rabbits and accelerated weight gain without changing overall feed intake. The underlying reason was that DF disturbed the lipid metabolism rhythms, promoted hepatic lipid synthesis regulated by DGAT1 and lipid synthesis of adipose tissues regulated by GPAM, thus triggering fat deposition. In contrast, the NRF regimen enhanced thermogenesis regulated by T3 and elevated body temperature and facilitated ketogenesis mediated by HMGCS2, increasing energy consumption. However, it had no significant impact on the fat content within muscle. This study offers a theoretical foundation for the refinement of feeding management and healthy raising of rabbits.