MODELLING THE APPLICATION OF THE IDEAL PROTEIN CONCEPT IN FISH AND SHRIMP  

The ideal protein concept (IPC), sometimes called the ideal amino acid concept, works on the premise that an animal requires the ten proteinogenic essential amino acids (EAA) in a ratio relative to lysine (or some other quantitatively determined amino acid) as defined by their own natural body amino acid composition (Table 1). Using a quantitative determination of a key amino acid this ratio is then applied to define the quantitative requirements of all the other EAA. Because of this relationship and the capacity to model protein and energy demand, using standard factorial bioenergetic modelling (FBM) methods, by extension it also becomes possible to model demand for each of the ten essential amino acids.

There are several steps to facilitating this modelling of the quantitative requirements for the ten EAA. The first step is to have a factorial bioenergetic model that predicts energy and protein demand of a healthy, growing animal. This requires a predictive growth model, a series of body composition equations, and determining key utilisation coefficients of energy and protein and having estimates of maintenance requirements for energy and protein. In addition to these standard parameters for development of a FBM, we also need a robust analysis of the amino acid composition of the whole animal with varying body size. This information then needs to be paired with a similarly robust assessment of the quantitative requirements for any of the EAA, usually as defined using a simple dose-response study. Each of these different parameters can then be integrated together to create an adaptation of the FMB that includes predicative outputs for the EAA.

In this paper, we will explore the application of the IPC in combination with the FBM to define the quantitative requirements for each of the ten EAA across five key aquaculture species. From these derived estimates, we will then compare and contrast across species and different animal sizes to assess the robustness of this modelling strategy for this application.