Viability of dietary substitution of live microalgae with dry Ulva rigida in broodstock conditioning of the Pacific oyster (Crassostrea gigas)

• Published in: Biology Open
• Main Authors: Rato A., Joaquim S., Tavares T.G., Martins Z.E., Guedes A.C., Pereira L.F., Machado J., Matias A.M., Gonçalves J.F.M., Vaz-Pires P., Magnoni L.J., Ozório R.O.A., Matias D.
• Other Authors: CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental
• Format: Article in Journal/Newspaper
• Language: English
• Published: Company of Biologists 2018
• Subjects: animal experiment; animal tissue; Article; biochemical composition; carbohydrate intake; Chaetoceros; Chaetoceros calcitrans; controlled study; Crassostrea gigas; diet; fat intake; female; fertilization; gametogenesis; glycogen analysis; gonad development; hatchery; histology; Isochrysis galbana; maturation; microalga; nonhuman; protein content; protein intake; reproductive success; Skeletonema; Skeletonema costatum; spawning; Ulva; Ulva rigida; veliger; Pacific; Pacific oyster
• Online Access: https://hdl.handle.net/10216/120510; https://doi.org/10.1242/bio.035923

The current study evaluated the microalgae replacement by dry macroalgae (Ulva rigida) in the reproductive success and biochemical composition of the Pacific oyster (Crassostrea gigas) during broodstock conditioning. Five nutritional regimes were tested: 100% macroalgae (diet 1), 50% macroalgae+50% microalgae (diet 2), 25% macroalgae+75% microalgae (diet 3) and 100% microalgae (diet 4). An unfed group was used as a negative control. The microalgae blend was composed of 33% Isochrysis galbana and 67% diatoms (75% Skeletonema costatum+25% Chaetoceros calcitrans). Gonadal maturation was reflected in the physiological condition of the individuals. All treatments, except diet 1, showed an increase in condition index and were fully matured at the end of the trial, with the best physiological condition observed in oysters fed diet 3 and diet 4. Protein and total lipid content increased during the conditioning period, whereas glycogen content decreased. Oysters conditioned with diet 3 had higher protein and total lipid content and lower glycogen content than the other treatments. In addition, diet 3 showed the highest percentage of viable veliger larvae. The current study demonstrated that it is possible to replace 25% of microalgae with macroalgae in the broodstock conditioning, minimizing the operative cost in bivalve hatcheries. © 2018. Published by The Company of Biologists This work was supported by Project INNOVMAR-Innovation and Sustainability in the Management and Exploitation of Marine Resources [NORTE-01-0145-FEDER-000035] within the line ‘INSEAFOOD, Innovation and valorization of seafood products’, funded by the Northern Regional Operational Programme (NORTE2020) through the European Regional Development Fund. Postdoctoral fellowships were granted to authors T.G.T. [SFRH/BPD/89360/2012] and to author A.C.G. [ref. SFRH/ BPD/72777/2010], by Fundaçaõ para a Ciência e a Tecnologia (Portugal), under the auspices of ESF and Portuguese funds. Z.E.M. is grateful to the project [UID/QUI/ ...