Impact of the replacement of dietary fish oil by animal fats and environmental salinity on the metabolic response of European Seabass (Dicentrarchus labrax)

Publication date: Available online 18 April 2019Source: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular BiologyAuthor(s): Francisca Silva-Brito, Filipa Timóteo, Ângela Esteves, Maria João Peixoto, Rodrigo Ozorio, Leonardo MagnoniAbstractThe replacement of fish oil (FO) with other lipid sources (e.g. animal fats, AF) in aquafeeds improves the sustainability of aquaculture, even though alternatives have different fatty acid (FA) profiles. FO contains a higher proportion of long-chain polyunsaturated fatty acids (LC-PUFAs) than AF. LC-PUFAs have key physiological roles, despite limited biosynthetic capacity in marine fish. Therefore, replacing FO in feeds may limit physiological responses when fish face environmental challenges such as an acute change in salinity. To test this hypothesis, juvenile seabass (62.6 ± 1.6 g, 50 fish/ 500 L tank) were fed three different isoproteic and isolipidic diets in which the replacement levels of FO by AF varied (0%, 75% or 100% AF). Fish were fed the experimental diets at 2% their body weight (BW) daily for 85 days (20.0 ± 1.0 °C; 35‰). Thereafter, half of the fish were transferred to tanks at 15‰ or 35‰ salinity and sampled at 24 h and 72 h. Plasma osmolality, Na+, glucose, cholesterol and lactate levels were altered by the changing salinity, although cortisol remained unchanged. Standard metabolic rate was similar irrespective of the experimental factors. However, maximal metabolic r...
Source: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology - Category: Molecular Biology Source Type: research