An individual based model for estimating nutritional value of rotifers (Brachionus plicatilis) as start feed for fish larvae

A dynamic individual based model is being developed with the purpose of describing population dynamics and individual body composition of rotifers in culture or when used as feed for cold-water fish larvae. This model can form the basis for optimizing several aspects of larva production. The individual model is a dynamic energy budget net assimilation model with several energy reserves and structural volume compartments. Rotifer body composition is described in terms of protein and lipid content per individual, as well as the content of specific nutrients that must be provided in sufficient quantity for the fish larvae. A large set of super individuals are simulated, each representing a variable number of rotifers. This structure allows the model to describe a population of individuals with varying age, energy state and egg count, which is necessary to predict population dynamics. For enriched rotifers added to larval start feeding tanks, body composition varies with residence time. The model can be used to describe the dynamic effects of enrichment, and in combination with a feed intake model for the fish larvae, the actual nutritional value of the ingested live feed can be estimated.