Browsing by Author "Dias, Jorge"
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- Chlorella vulgaris extracts as modulators of the health status and the inflammatory response of gilthead seabream juveniles (Sparus aurata)Publication . Reis, Bruno; Ramos-Pinto, Lourenço; Cunha, Sara A.; Pintado, Manuela; Silva, Joana Laranjeira da; Dias, Jorge; Conceição, Luís; Matos, Elisabete; Costas, BenjamínThis study aimed to evaluate the effects of short-term supplementation, with 2% Chlorella vulgaris (C. vulgaris) biomass and two 0.1% C. vulgaris extracts, on the health status (experiment one) and on the inflammatory response (experiment two) of gilthead seabream (Sparus aurata). The trial comprised four isoproteic (50% crude protein) and isolipidic (17% crude fat) diets. A fishmeal-based (FM), practical diet was used as a control (CTR), whereas three experimental diets based on CTR were further supplemented with a 2% inclusion of C. vulgaris biomass (Diet D1); 0.1% inclusion of C. vulgaris peptide-enriched extract (Diet D2) and finally a 0.1% inclusion of C. vulgaris insoluble fraction (Diet D3). Diets were randomly assigned to quadruplicate groups of 97 fish/tank (IBW: 33.4 ± 4.1 g), fed to satiation three times a day in a recirculation seawater system. In experiment one, seabream juveniles were fed for 2 weeks and sampled for tissues at 1 week and at the end of the feeding period. Afterwards, randomly selected fish from each group were subjected to an inflammatory insult (experiment two) by intraperitoneal injection of inactivated gram-negative bacteria, following 24 and 48 h fish were sampled for tissues. Blood was withdrawn for haematological pro-cedures, whereas plasma and gut tissue were sampled for immune and oxidative stress parameters. The anterior gut was also collected for gene expression measurements. After 1 and 2 weeks of feed-ing, fish fed D2 showed higher circulating neutrophils than seabream fed CTR. In contrast, dietary treatments induced mild effects on the innate immune and antioxidant functions of gilthead sea-bream juveniles fed for 2 weeks. In the inflammatory response following the inflammatory insult, mild effects could be attributed to C. vulgaris supplementation either in biomass form or extract. However, the C. vulgaris soluble peptide-enriched extract seems to confer a protective, anti-stress effect in the gut at the molecular level, which should be further explored in future studies.
- Unravelling the effects of extrusion and drying temperatures on the radical scavenging capacity of aquafeeds supplemented with mango and pineapple by-productsPublication . Pereira, Ricardo; Velasco, Cristina; Gómez-Garcia, Ricardo; Dias, Jorge; Pintado, Manuela; Valente, Luisa M. P.Antioxidant supplementation of aquafeeds with natural sources is a current research trend within the context of a circular economy. However, natural antioxidants are highly vulnerable to thermal conditions during feed manufacturing, particularly during extrusion and drying. This study examines the impact of extrusion and drying temperatures on the antioxidant properties of aquafeeds supplemented with natural antioxidants from mango and pineapple peels. A control dietary mixture and two dietary mixtures with 2 % inclusion of either mango (M) or pineapple (P) peel flour were subjected to different combinations of extrusion temperatures (110 °C, -H vs 25 °C - C) and drying temperatures (60 °C vs 35 °C). Ingredients, manufacturing process intermediate stages, and final diets were analysed for their natural antioxidant composition (vitamins, carotenoids, free and fibre-bound phenolic compounds) and antioxidant capacity via the DPPH+, ABTS•+ and ORAC assays, the latter of which is the most representative for biological models. Results show that incorporating 2 % of either pineapple or mango peel flour increases the antioxidant content and capacity of aquafeeds compared to a control diet subjected to the same manufacturing conditions. Phenolic compounds were more abundant and resistant to the feed manufacturing process than vitamins and carotenoids. Specifically, ORAC results for free and fibre-bound extracts in diet PH-60 (1674.3 and 1216.2 mg TE 100 g DM−1, respectively) were significantly higher (P < 0.001) than the control CH-60 (694.8 and 422.8, respectively). Moreover, free extracts from diet PC-60 (1312.0 mg TE 100 g DM−1) and fibre-bound extracts from diets MH-60 and PH-35 (719.2 and 871.1 mg TE 100 g DM−1, respectively) were also significantly higher than the control (P < 0.001). A PCA analysis showed that pineapple diets with hot extrusion, as well as the mango diet with hot extrusion and hot drying, are more closely associated with higher antioxidant capacity in both free and bound extracts. Overall, fruit peel flours show promise as antioxidant supplements for mitigating oxidation in aquafeeds.