Application of in vitro digestibility methods in aquaculture: constraints and perspectives

In vitro assays simulating the digestion process have been extensively used in the evaluation of the nutritional quality of foods and feeds for humans and terrestrial animals. Such techniques have been comparatively less used in nutrition of aquacultured species, although in recent years the interest in developing alternatives to the conventional in vivo digestibility assays has increased. Using 65 published papers as a reference, this review summarizes the different approaches and configurations used to date in the simulation of the digestion of food by aquatic animals, as well as the main limitations detected in the different methods and the potential advantages derived from their application. Some recommendations are suggested to develop suitable in vitro assays oriented either to the nutritional evaluation of feed ingredients or to get a more detailed knowledge on the interactions among digestive enzymes and feed components.