Effects of dietary supplementation of Gracilaria sp. extracts on fillet quality, oxidative stress, and immune responses in European seabass (Dicentrarchus labrax)
The current study evaluated the effects of two different fractions derived from the methanolic extraction of the red seaweed Gracilaria sp. supplemented in European seabass (Dicentrarchus labrax) diets. With that purpose, three experimental diets were prepared: a basal diet (control), a control supplemented with the methanolic extract (GE, 0.5% diet) and a control supplemented with the insoluble residue of the GE extraction (GR, 4.5%). Seabass with an average initial weight of 16.5 ± 0.6 g were fed the experimental diets for 42 days, and the following parameters were evaluated: growth indicators, digestive enzyme activities, immune and oxidative stress responses, fillet pH and color (L*, a*, and b* values), and skin color. The dietary supplementation of GE or GR had no effect on growth performance, digestive enzyme activities, fillet pH, and color. Skin color was significantly lighter (L*) in fish-fed GE (83.9 ± 1.9) and GR (84.3 ± 2.3) diets when compared with the control group (81.9 ± 3.8). The dietary treatments did not affect the oxidative stress biomarkers. Alternative complement pathway (ACH50) was significantly higher in fish-fed GE diet (168.2 ± 13.4 EU mL−1) than in the control diet (113.1 ± 31.4 EU mL−1). No dietary effect was observed on peroxidase and lysozyme activities. The current study indicates that dietary supplementation of Gracilaria sp. methanolic extracts may have little influence on the innate immune system and skin color in seabass.
KeywordsDicentrarchus labrax Gracilaria sp. extract Rhodophyta Fillet quality Dietary seaweed supplementation Fish welfare
The authors thank E. Blom for assistance with purchase of the fish, A. Hofman and Y. van Es for assistance with animal care, J. Kals and W. Abbink for scientific support, and H. van de Vis for instructions on measuring fillet pH and color and interpretation of the results.
This study has been part of an AQUAEXCEL application for DLO-IMARES research infrastructure with reference code 0094/07/15/32/B and the project INNOVMAR-Innovation and Sustainability in the Management and Exploitation of Marine Resources (reference NORTE-01-0145-FEDER-000035), within the Research Line INSEAFOOD, funded by the Northern Regional Operational Programme (NORTE 2020) through the European Regional Development fund (ERDF).
Compliance with ethical standards
All procedures were conducted under the supervision of an accredited expert in laboratory animal science by the Portuguese Veterinary Authority (1005/92, DGV-Portugal, following FELASA category C recommendations) according to the guidelines on the protection of animals used for scientific purposes from the European directive 2010/63/UE. The experiment took place at the aquaculture facilities of the Institute for Marine Resources and Ecosystem Studies (IMARES; now Wageningen Marine Research—WMR, Yerseke, The Netherlands) that complied with the current laws of the Netherlands and were approved by the animal experimental committee (DEC no. 2014085).
- Bojanić K, Kozačinski L, Filipović I, Fleck ŽC, Zdolec N, Njari B (2009) Quality of sea bass meat during storage on ice. Meso 11:44–49Google Scholar
- El-Tawil NE (2010) Effects of green seaweeds (Ulva sp.) as feed supplements in red Tilapia (Oreochromis sp.) diet on growth performance, feed utilization and body composition. J Arabian Aquac Soc 5:179–193Google Scholar
- Ganeshamurthy R, Dhayanithi NB, Kumar TTA, Kumaresan S (2014) Evaluation of antibacterial activity and immunostimulant of red seaweed Chondrococcus hornemanni (Kuetzing, 1847) against marine ornamental fish pathogens. J Coast Life Med 2:64–69Google Scholar
- Horwitz W, Latimer GW, Association of Official Analytical Chemists I (2006) Official methods of analysis of AOAC International. AOAC International, GaithersburgGoogle Scholar
- Huggett RJ (1992) Biomarkers: biochemical, physiological, and histological markers of anthropogenic stress. Lewis Publishers, New YorkGoogle Scholar
- Kime DE (2012) Endocrine disruption in fish. Springer, New YorkGoogle Scholar
- Moroney NC, Wan AH, Soler-Vila A, FitzGerald RD, Johnson MP, Kerry JP (2015) Inclusion of Palmaria palmata (red seaweed) in Atlantic salmon diets: effects on the quality, shelf-life parameters and sensory properties of fresh and cooked salmon fillets. J Sci Food Agric 95:897–905CrossRefGoogle Scholar
- Peixoto MJ, Salas-Leitón E, Pereira LF, Queiroz A, Magalhães F, Pereira R, Abreu H, Reis PA, Gonçalves JFM, Ozório ROA (2016a) Role of dietary seaweed supplementation on growth performance, digestive capacity and immune and stress responsiveness in European seabass (Dicentrarchus labrax). Aquac Rep 3:189–197CrossRefGoogle Scholar
- Peixoto MJ, Svendsen J, Malte H, Pereira L, Carvalho P, Pereira R, Gonçalves JM, Ozório RA (2016b) Diets supplemented with seaweed affect metabolic rate, innate immune, and antioxidant responses, but not individual growth rate in European seabass (Dicentrarchus labrax). J Appl Phycol 28:2061–2071CrossRefGoogle Scholar
- Repetto M, Semprine J, Boveris A (2012) Lipid peroxidation: chemical mechanism, biological implications and analytical determination. In: Catala A (ed) Lipid peroxidation. InTech, Rijeka, pp 3–30Google Scholar
- Ringø E, Olsen R, Vecino J, Wadsworth S, Song S (2012) Use of immunostimulants and nucleotides in aquaculture: a review. J Mar Sci Res Dev 1:104Google Scholar
- Sangeetha S, Dhayanithi NB, Natesan S (2014) Antibacterial activity of Sargassum longifolium and Gracilaria corticata from Gulf of Mannar against selected common shrimp pathogens. Int J Pharma Bio Sci 5:76–82Google Scholar