LAUSR

EnglishImplementation of mixture models in isotopic analysis has been increasing due to the need to analyze sources and understand their variations in relation to consumers, which requires an accurate determination of their discriminant rate and fractioning. In this context, we presented the main concepts related to the application of stable isotopes and mixing models, with the aim to analyze the benefits and problems of these tools in surveys on nutrition of aquatic organisms. The predominant methods identified included application of the models IsoSource, MixSIR, SIBER and SIAR, with the use of C and N isotopes in research with aquatic organisms. Studies in both freshwater and marine environments were evaluated to determine the relative contribution of the main food items and understand trophic relationships between organisms. It can be concluded that the application of mixing models, with the stable isotope technique, is a promising tool for research on feeding aquatic organisms and understanding issues related to trophic ecology of these organisms. Key words: food; nutrition; diets; fish. portuguesOs modelos de mistura nas analises isotopicas vem sendo cada vez mais utilizados devido a necessidade de analisar as fontes alimentares e compreender suas variacoes em relacao aos consumidores, o que requer uma adequada determinacao de suas taxas discriminantes e fracionamentos. Neste contexto, objetivamos apresentar os principais conceitos relacionados a aplicacao de isotopos estaveis e modelos de mistura, visando analisar as vantagens e desvantagens destas ferramentas em pesquisas com nutricao de organsimos aquaticos. Foram identificados de forma predominante a aplicacao dos modelos IsoSource, MixSIR, SIBER e SIAR, com a utilizacao dos isotopos de C e N em pesquisas com organismos aquaticos, tanto em ambientes dulcicolas como em ambientes marinhos para determinar a contribuicao relativa dos principais itens alimentares e compreender relacoes troficas entre organismos. Pode-se concluir que, a aplicacao dos modelos de mistura com a tecnica de isotopos estaveis compoe uma ferramenta promissora nas pesquisas sobre alimentacao de organismos aquaticos e na compreensao de questoes relacionadas a ecologia trofica destes organismos. Palavras-chave: alimento; nutricao; dietas; peixe