Optimum level and ratio of dietary cholesterol and lecithin for megalopae of the spider crab, Maja brachydactyla: preliminary experimental assessments


Contact
Klaus.Anger [ at ] awi.de

Abstract

The spider crab, Maja brachydactyla (Decapoda: Brachyura: Majidae), has been recently considered a potential species for aquaculture. Adult M. brachydactyla were captured off the Atlantic coast of Spain (Galicia), transported to IRTA, subsequently kept at a salinity of 36 and a temperature of 18°C, and fed (fresh mussels and frozen crab). When spawning took place, newly hatched larvae were transferred to 35 L PVC baskets (with a 150 µm mesh-bottom) suspended in 1500 L tanks. Larvae were stocked at a density of 60 zoeae·L-1 and fed with 60 enriched Artemia metanauplii (EAM)·larva-1 per day. Between days 8 and 10 post-hatching, ZII larvae (at molt stage D2) were transferred from the baskets into 500 mL beakers without food supply. Upon molting, they were transferred to 100 mL beakers placed in a water bath, where temperature was maintained at 18ºC. In each beaker, only one megalopa was introduced to avoid cannibalism. Treatments were as follows: positive control (C+): fed daily with 7.2 EAM·mL-1; negative control (C-): without food supply; treatment (T) 1: 4% lecithin + 3% cholesterol diet; T2: 2% lecithin + 3% cholesterol diet; T3: 4% lecithin + 1% cholesterol diet; and T4: 2% lecithin + 1% cholesterol diet. Every morning, water was renewed in each beaker, mortality and molting was noted, and animals fed. C+ was fed once, while T1 to T4 were fed twice per day (10 am and 4 pm). On day 4, when megalopae reached the premolt stage (D0), 5 larvae per treatment were sampled to analyze their biomass (dry weight, DW; CHN). In animals fed with EAM (C+) and T1-type microdiet, megalopae metamorphosed on day 6 or 7. On day 4, survival was over 20% in megalopae in groups C+, T1 and T4. Larvae in C+ and T1 were significanly heavier (DW) and presented higher N (i.e. protein) levels than larvae from treatments T2, T3, T4 and C-. These preliminary results suggest that a 2:1 lecithin:cholesterol ratio may satisfy the nutritional requirements of spider crab megalopae.



Item Type
Conference (Poster)
Authors
Divisions
Programs
Peer revision
Not peer-reviewed
Publication Status
Published
Event Details
International Symposium on Aquaculture, Biology and Management of Commercially Important Crabs 2009 (ISABMC-2009) November 8-11, 2009 Shanghai, China..
Eprint ID
21254
Cite as
Rotllant, G. , Zeng, C. , Andrés, M. , Guerao, G. , Estévez, A. and Anger, K. (2009): Optimum level and ratio of dietary cholesterol and lecithin for megalopae of the spider crab, Maja brachydactyla: preliminary experimental assessments , International Symposium on Aquaculture, Biology and Management of Commercially Important Crabs 2009 (ISABMC-2009) November 8-11, 2009 Shanghai, China. .


Share

Research Platforms
N/A

Campaigns


Actions
Edit Item Edit Item