Isotopic techniques in aquaculture nutrition: State of the art and future perspectives
Julián Gamboa‐Delgado
Abstract
Abstract Animal nutrition studies rely on traditional and advanced analytical techniques that have increased our understanding about the nutritional physiology of valuable species, leading to improved productivity, sustainability and further diversification. In the case of aquaculture nutrition, a vast amount of knowledge has accumulated in relation to different physiological responses elicited by experimental diets and feeding regimes. By measuring assimilation, inferences can be made about the specific dietary components that were digested, incorporated into tissue and used for metabolic functions. One of the most common methods applied to estimate assimilation consists of measuring stable isotope values at natural abundance levels in feeding items and consuming animals. Isotopic measurements have been of great assistance to identify nutrient sources contributing to the growth of larval and juvenile organisms. The techniques have also been useful to determine nutrient flows in several types of aquaculture systems. The present manuscript reviews the most recent applications and findings derived from studies that have used stable isotope analyses to (1) estimate nutrient assimilation in larval and juvenile organisms, (2) evaluate trophic dynamics and bioremediation potential of macroalgae and invertebrates in integrated multi‐trophic aquaculture systems and (3) investigate the trophic plasticity of aquatic species. The progressively more frequent application of compound‐specific isotope analysis of amino acids and fatty acids is emphasized as it has allowed exploring the physiological fate of specific organic compounds, while also assisting in the definition of nutritional requirements for aquatic species. Future nutritional applications of analytical techniques based on stable isotope measurements are addressed.