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

## TL;DR

Feeding rabbits during the day in winter disrupts their metabolism and increases fat, while nighttime feeding helps maintain healthy rhythms and reduces fat accumulation.

## Contribution

This study reveals how feeding timing affects metabolic rhythms and lipid accumulation in rabbits during winter.

## Key findings

- Daytime feeding disrupts metabolic rhythms and increases lipid accumulation in rabbits during winter.
- Nighttime restricted feeding improves circadian gene expression and reduces fat deposition.
- NRF enhances thermogenesis and energy consumption without affecting muscle fat content.

## Abstract

With the ceaseless advancement of intensification and automation in the rabbit industry, the implementation of precise feeding management is urgently needed. Disruptions to the feeding routine, exposure to stress, and fluctuations in environmental temperatures can upset animals’ circadian rhythms, thereby disturbing their metabolic equilibrium and impairing both health and productivity. We plan to seek ways to enhance rabbits’ welfare and production by optimizing feeding strategies. Five-week-old rabbits were assigned to the daytime feeding (DF) group and nighttime restricted feeding (NRF) group. The results proved that, during the winter, daytime feeding disrupted metabolic rhythm and increased lipid accumulation of growing rabbits in winter. In contrast, NRF significantly improved the rhythmic expression of clock genes in peripheral tissues such as the liver, muscle, and adipose tissue, ultimately reducing lipid deposition.

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.