A dynamic model of nutrient pathways, growth, and body composition in fish

Abstract

The growth and body composition of an organism are dynamic and depend on available diet, as well as other environmental variables. A structured model is described predicting growth, body composition, and the first limiting amino acid for a variety of feeding regimes over a relatively long time scale. This model continuously provides, as a function of time, the flow of nutrients and metabolites through the principal metabolic pathways leading to tissue growth. Measurements of growth and whole body composition (including amino acid composition) from a large-scale experiment with Atlantic salmon (Salmo salar) have been employed to calibrate this model. Comparisons of simulations with the results of feeding experiments validate the predictive ability of the model. These types of simulations will be valuable in studying the quantitative relationships between intracellular energy levels and nutrient distribution in tissues. They will also provide data for balancing diet composition and amino acid profile in order to optimize growth with respect to factors such as body weight, body composition, and ambient temperature. As a result of its modularity, the model can be easily extended to include additional physiological and metabolic processes.