TROPICAL CORALS NUTRITION: ARE MICROENCAPSULATED DIETS SUITABLE TO IMPROVE GROWTH PERFORMANCE?
The increasing demand of tropical corals led to the need of a sustainable supply solution without compromising natural stocks, already affected by climate change and anthropogenic activities. Ex situ coral aquaculture can be a suitable option to fulfill coral needs. However, it is important to consider species requirements to optimize production.
Four coral species with market value were selected (Octocorals - Sinularia brassica , Sarcophyton glaucum ; and hexacorals - Zoanthus sp. and Palythoa sp.). Four feeding regimes were tested: (i ) non feed - NF; feed with microencapsulated experimental diets (2 times per week, 580 µg L-1 ) formulated by SPAROS, based on (ii) squid and fish meal - SFM, (iii ) artemia - ART, and (iv ) microalgae - ALG. The experiment was performed in 500 L RAS with artificial illumination, during 5 months. Before and after this period, corals were sampled to determine: survival; growth (by p hotogrammetry of octocorals and polyp count of hexacorals ); in vivo chlorophyll fluorescence - maximum quantum yield of photosystem II (Fv/Fm); and biochemical biomarkers of cellular energy allocation.
Survival was 100% in all treatments. S . brassica growth was significantly improved with ALG, while S . glaucum showed better growth performance with ART (F ig. 1). Hexacorals exhibited a general growth increase when supplied with SFM. ART and ALG diets induced higher metabolism in octocorals . Fv/Fm was within healthy range for studied species in all treatments.
This study highlights that species-specific requirements must be considered for achieving a sustainable and economically viable coral aquaculture. Yet, as corals are slow-growing species, we hypothesize that differences between tested feeds may be further emphasize if experiments take place over longer periods (e.g. more than 1 year).
