A dynamic mathematical model to study the flexibility of energy reserves in adipose and muscle cells

Masoomeh Taghipoor (1) , Jaap J. van Milgen (1) , Florence Gondret (1)

1 PEGASE - Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'Elevage [Rennes]

Animals need energy for their basal metabolism and productive functions. When dietary energy intake exceeds energy expenditure, the excess is stored as glycogen and triacylglycerols (TG) in cells. The dynamics of uptake, oxidation and storage of nutrients at the cellular level are very important to understand tissue composition and to predict the effects of different sources of energy supply to animals. A dynamic model was developed to investigate the plasticity of energy stores into a generic cell. This model was based on a system of coupled ordinary differential equations, with each equation representing a single biochemical reaction or successive transformations of intermediate metabolites. Reaction rates were regulated by the activities of enzymes involved in the reactions. The ATP/ADP ratio was assumed to be the main intracellular signal to switch between storage and oxidation pathways. Cellular uptake of glucose and free fatty acids was modeled in a continuous or discontinuous phenomenon during the day. Simulations included the time-dependent evolution of glycogen and TG in the cell. Because of its generic aspect, the model can be used to study muscle or adipocyte metabolism by changing the basic parameters. Further development would include hormone signals regulating the partitioning of nutrients between muscle and adipose cells, and the coupling between hypertrophy and hyperplasia in tissue development. In conclusion, the model provides a dynamic framework to investigate relevant hypotheses in farm animal production, including the postprandial metabolism (fast dynamics) and fexibility of energy reserves in response to changes in feed intake, physical activity or growth (slow dynamics).

Domaines: Alimentation et Nutrition; Biologie du développement; Biologie animale

Masoomeh Taghipoor, Jaap J. van Milgen, Florence Gondret. A dynamic mathematical model to study the flexibility of energy reserves in adipose and muscle cells. 65. Annual Meeting of the European Federation of Animal Science (EAAP), Aug 2014, Copenhague, Denmark. Wageningen Academic Publishers, Annual Meeting of the European Association for Animal Production, 20, 2014, Annual Meeting of the European Association for Animal Production. ⟨hal-01210668⟩