Live microalgae as feeds in aquaculture hatcheries

Brown and S. I. Blackburn, CSIRO Marine and Atmospheric Research, Australia 

Key words aquaculture feeds, hatchery, larvae, microalgae, live feeds, photobioreactor. 

Microalgae, the microscopic plants present in oceans and waterways, are exploited as an indispensible food source for the commercial production of many aquaculture species. Within the hatchery environment, they are directly eaten by all growth stages of bivalves (broodstock, larvae, juveniles), post-set abalone, the larval stages of some crustacean species, and the very early developmental stages of some fish species. Microalgae are also used as feed to culture zooplankton (e.g. Anemia, rotifers, copepods) that are used as food for larval and juvenile stages of many fish and crustacean species. 

This chapter reviews the production and use of microalgae within aquaculture hatcheries. The compositional diversity of microalgae is firstly discussed, with emphasis on the concentrations of nutritionally important 

The amino acid composition of the protein fraction is very similar between different microalgae and relatively unaffected by light and nutrient conditions (Brown et al, 1997 Daume et al., 2003). On this basis, it is unlikely that protein quality is a major factor contributing to differences in the nutritional value of microalgae. 

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Live microalgae as feeds in aquaculture hatcheries 119 4.2.2 Amino acids and carbohydrates... 

With the development of the aquaculture industry and the need by hatcheries to rear larval and juvenile aquaculture animals came the need for production of microalgae as live feeds. While some hatcheries grow microalgae in multiples of relatively small scale culture containers, for example 20 litre carboys, it is more common for miCToalgal cultures to be grown in disposable plastic bags (200-1000 litres is typical) that are either supported vertically (Plate 9.1b) in metal frames or lie horizontally. 

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