Optimization of an in-vitro bioaccessibility fish model

• Autor(a) principal: Silva, Pedro Miguel da Graça
• Data de Publicação: 2023
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/161443
• topic: In vitro digestion methods; Fish; Fish feed; Bioaccessibility; Protein content; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Recent advances in aquaculture nutrition have raised the interest on studies regarding new feed products capable of effectively replacing fish meal and oil, which must be thoroughly analyzed in terms of their nutrient bioaccessibility in order to certify their efficacy. In vitro models could allow the assessment of the bioaccessibility of nutrients, particularly proteins, in fish meal replacements, in a faster and less expensive manner when taken into consideration the in vivo approach, without requiring the use of living organisms or being dependent on their physiological state. To date, there are few studies focused on simulating the fish gastrointestinal tract in vitro, to quantify the feed digestibility, bioaccessibility and bioavailability of nutrients, which motivates further efforts to develop and validate fish digestive in vitro models. This study aimed to develop and optimize a static in vitro digestion model for marine fish capable of assessing the bioaccessibility of proteins, using a juvenile fish species (gilthead seabream, Sparus aurata) as biological model. Three different procedures were tested to conduct the bioaccessibility analyses of the obtained samples, namely with EMA, a nitrogen total high range kit and with LECO, the latter being the instrument more optimized to perform this type of analyses, providing the most reliable results. The results obtained with one of the protocols tested, using commercial enzymes, were promising, revealing high values of bioaccessibility that seem to confirm the efficacy of the digestive process, with the highest value being recorded in the following conditions: 250 mg of feed, a temperature of 37 ºC and a digestion process of 24 hours. However, such results will need to be validated with an in vivo experiment. Ultimately, this study intended to provide a contribution to the attainment of a robust model adequate to assess the efficacy of fish meal replacements and new aquafeeds, that in turn could contribute to the achievement of a truly sustainable aquacultural development, while ensuring the acquisition of aquaculture products with high quality for commercialization.