Evaluation of bioavailability of omega-3 lipids from Tetraselmis chui in zebrafish model

• Autor(a) principal: Sequeira, Inês Francisco
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/36738
• topic: Microalgae; Tetraselmis chui; Lipids; Omega-3 fatty acids; Zebrafish; Feeding; Bioaccessibility; Bioavailability

Tetraselmis chui (T. chui) is a unicellular green microalga approved for human consumption with a high content of omega-3 polyunsaturated fatty acids (PUFAs), including alfa-linolenic acid and eicosapentaenoic acid. These lipids have bioactive properties such as antioxidant and anti-inflammatory, and can be used in the food, pharmaceutical, and cosmetic industries. These PUFAs are mostly found esterified in polar lipids (phospholipids and glycolipids), which has been linked to an increase in their bioavailability. This is noteworthy because the potential bioactivity and nutritional value of these lipids is closely related to their bioaccessibility and bioavailability. However, this topic is poorly explored on omega-3 PUFAs from microalgae, specifically from T. chui. Thus, this work aimed to (a) study the variation of the lipid profile of zebrafish fed with a commercial diet (GEMMA) along two life stages: juvenile (35 days post fertilization) and adult (65- and 95-days post fertilization), and (b) evaluate the bioavailability of omega-3 PUFAs obtained from a diet enriched in T. chui biomass (50% GEMMA + 50% T. chui). The fatty acids (FAs) profile was analyzed by GC-MS and the characterization of the polar lipidome by LC-MS. The FAs profile was maintained through the development and the most abundant FAs identified were C16:0, C18:0, C18:1Δ⁹, C18:2Δ⁹˒¹², and C22:6Δ⁴˒⁷˒¹⁰˒¹³˒¹⁶˒¹⁹. Multivariate statistical analysis of the polar lipid profile showed variations in the molecular species profile of sphingomyelin (SM), phosphatidylethanolamine (PE), ceramides (Cer), phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and phosphatidic acid (PA). The incorporation of T. chui biomass in the diet did not induce significant differences in the zebrafish FAs profile. However, it was observed an increase in the relative abundance of molecular species of PC, phosphatidylserine (PS), PE, and phosphatidylinositol (PI) rich in omega-3 fatty acids namely C22:6Δ⁴˒⁷˒¹⁰˒¹³˒¹⁶˒¹⁹, C22:5Δ⁷˒¹⁰˒¹³˒¹⁶˒¹⁹, and C20:5Δ⁷˒¹⁰˒¹³˒¹⁶˒¹⁹. Future research on the polar lipidome of T. chui is needed to correlate it with the variations observed in the zebrafish lipidome. Aside from that, more research is needed to analyze the changes in the neutral lipid profile of zebrafish in response to dietary changes. Diets enriched with different amounts of this microalga or combining different microalgae can also be tested, as well as studying biomarkers of antioxidant and anti-inflammatory activity, in order to relate the bioactive properties of T. chui polar lipids with the potential health effects on zebrafish.