Acuacultura En Mexico

Nutritional Value and Use of Microalgae in Aquaculture
Malcolm R. Brown
CSIRO Marine Research, GPO Box 1538, Hobart, 7001 Australia email: malcolm.brown@csiro.au ABSTRACT This review provides a background on the usage of microalgae in aquaculture, focusing on their nutritional value and transfer of nutrients through food chains. The current status of knowledge is summarized and potential areasof research and industry development are identified. The review is divided into six sections: (1) general attributes of microalgal species used in aquaculture, (2) nutritional properties, (3) production systems, (4) alternatives to fresh algae, (5) use of algae to enrich zooplankton and (6) directions for future research. GENERAL ATTRIBUTES OF MICROALGAE USED IN AQUACULTURE Microalgae are utilizedin aquaculture as live feeds for all growth stages of bivalve molluscs (eg. oysters, scallops, clams and mussels), for the larval/early juvenile stages of abalone, crustaceans and some fish species, and for zooplankton used in aquaculture food chains. Over the last four decades, several hundred microalgae species have been tested as food, but probably less than twenty have gained widespread usein aquaculture. Microalgae must possess a number of key attributes to be useful aquaculture species. They must be of an appropriate size for ingestion, e.g. from 1 to 15 µm for filter feeders; 10 to 100 µm for grazers (Webb & Chu, 1983; Jeffrey, LeRoi & Brown, 1992; Kawamura, Roberts & Nicholson, 1998) and readily digested. They must have rapid growth rates, be amenable to mass culture, and also bestable in culture to any fluctuations in temperature, light and nutrients as may occur in hatchery systems. Finally, they must have a good nutrient composition, including an absence of toxins that might be transferred up the food chain. Strains identified by Persoone & Claus (1980) as being successful for bivalve culture included Isochrysis galbana, Isochrysis sp. (T.ISO), Pavlova lutheri,Tetraselmis suecica, Pseudoisochrysis paradoxa, Chaetoceros calcitrans and Skeletonema costatum. It is noteworthy that now, over 20 years later, hatcheries are still using essentially the same strains for their production (Table 1).

Brown, M. R., 2002. Nutritional value of microalgae for aquculture. In: Cruz-Suárez, L. E., Ricque-Marie, D., Tapia-Salazar, M., Gaxiola-Cortés, M. G., Simoes, N. (Eds.).Avances en Nutrición Acuícola VI. Memorias del VI Simposium Internacional de Nutrición Acuícola. 3 al 6 de Septiembre del 2002. Cancún, Quintana Roo, México.

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Table 1. Microalgae commonly used in aquaculture, either as individual diets or components of mixed diets. (++ denotes more popular than +). Bivalve molluscs ++ ++ ++ + + + + + + + Crustacean larvae + + ++ ++ +++ + + + Juvenile abalone Zooplankton (used for crustacean, fish larvae) ++ ++ + + ++ ++ ++ + + ++

Isochrysis sp. (T.ISO) Pavlova lutheri Chaetoceros calcitrans C. muelleri or C. gracilis Thalassiosira pseudonana Skeletonema spp. Tetraselmis suecica Rhodomonas spp. Pyramimonas spp. Navicula spp. Nitzschia spp. Cocconeis spp. Amphora spp. Nannochloropsis spp.

References: Brown et al. (1997);Reitan et al. (1997); Lee (1997); Kawamura et al. (1998); Wikfors & Ohno (2001); Johnston per. comm. (CSIRO Collection of Living Microalgae)

Isochrysis sp. (T.ISO), Pavlova lutheri and Chaetoceros calcitrans are the most common species used to feed the larval, early juvenile and broodstock (during hatchery conditioning) stages of bivalve molluscs; these are usually fed together as a mixed diet(O’Connor & Heasman, 1997; Richard Pugh, Shellfish Culture Ltd., pers. comm.). Many of the strains successfully used for bivalves are also used as direct feed for crustaceans (especially shrimp) during the early larval stages, especially diatoms such as Skeletonema spp. and Chaetoceros spp. Benthic diatoms such as Navicula spp. and Nitzschia are commonly mass-cultured and then settled onto...