Stable isotope application in animal nutrition science

The application of stable isotope analysis (SIA) has become a standard scientific approach in Agricultural and Ecological researches and, more in general, in several disciplines such as biology, botany, zoology, organic chemistry, climatology, and nutrition. The main objectives of this paper are (1) to provide a simple definition of stable isotopes and (2) to illustrate analytical measurement methods and general applications in animal nutrition. The stable isotopes of carbon (Δ13C) and nitrogen (Δ15N) represent powerful tools to evalu-ate the trophic preferences of organisms and their trophic position. In association with Bayesian Mixing models, stable isotopes also enable the description of trophic links between species and, thus, of complex food webs. Stable isotope data should be complemented with additional dietary data on feeding behavior to provide information regarding the transfer of energy or nutrients. Nowadays, stable isotope analysis is em-ployed to address animal and human diets around the world.