A framework for the study of macronutrient intake in fish

A good understanding of the capabilities of commercially reared fish specie s to regulate intake of specific macronutrients has potential economic, wel fare and environmental benefits. We present a conceptual and experimental f ramework for studying macronutrient intake in fish. This 'geometric' approa ch addresses the multidimensional and interactive nature of nutrition. It w as developed from work on insect herbivores and has successfully been appli ed to mammals and birds. The various components of the framework are introd uced in simple outlines, and key experimental designs are described for ass essing whether or not fish specifically regulate their intake of macronutri ents, how they balance over-ingesting some nutrients against undereating ot hers when provided with suboptimal diets, and how they regulate growth post -ingestively.