Abstract
ABSTRACTThe 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.This article has an associated First Person interview with the first author of the paper.
Highlights
Pacific oysters Crassostrea gigas (Thunberg, 1793), a native species from northeast Asia was introduced worldwide, mainly to prevent crisis resulting from massive decline of indigenous population and to sustain aquaculture industries (Boudry et al, 1998)
The microalgae blend was composed by 33% Isochrysis galbana and 67% diatoms (75% Skeletonema costatum + 25% Chaetoceros calcitrans)
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
Summary
Pacific oysters Crassostrea gigas (Thunberg, 1793), a native species from northeast Asia was introduced worldwide, mainly to prevent crisis resulting from massive decline of indigenous population and to sustain aquaculture industries (Boudry et al, 1998). Aquaculture of bivalves is strongly dependent on the production of live microalgae, which represents 30-40% of the operative costs (Coutteau and Sorgeloos, 1992), constituting an economic limitation due to high costs of production, culture instability and batch variability (Arney et al, 2015; Borowitzka, 1997; Guedes and Malcata, 2012). To overcome this constraint and to reduce the use of live microalgae in bivalve hatcheries, several research lines have focused on evaluating alternative diets The aim is to find an alternative broodstock conditioning diet that maximizes fecundity and oocyte quality, being suitable to be used in commercial hatcheries
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call