Growth and proximate composition

Growth and proximate composition - Aquaculture Research...

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Growth and proximate composition of the Chaetoceros calcitrans f. pumilus under different temperature, salinity and carbon dioxide levels Gireesh Raghavan 1, Ã , Chanjaplackal Kesavan Haridevi 2 & Cherukara Purushothaman Gopinathan 1 1 Central Marine Fisheries Research Institute, Kochi, Kerala, India 2 National Institute of Oceanography, RC, Kochi, Kerala, India Correspondence: G Raghavan, Central Marine Fisheries Research Institute, Kochi, Kerala, India. E-mail: [email protected] Ã Present address: G Raghavan, NIO, RC, Kochi, Ernakulam North PO, Kochi 682018, Kerala, India. Abstract The marine diatom Chaetoceros calcitrans f. pumilus has been examined for its potential source as live feed in aquaculture.The present study investigated e¡ects of temperature (20,25 and 30 1 C), salinity (25 and 35) and carbon dioxide addition (air 1 CO 2 )o nt h e growth and proximate composition of C. calcitrans under laboratory conditions. The growth and bio- mass of C. calcitrans were primarily a¡ected by carbon dioxide addition, and to a lesser extent by temperature and salinity. In general, lipid and carbo- hydrate contents were higher at lower temperatures (20 and 25 1 C), while the protein content was unaf- fected. Carbon dioxide addition increased protein, while lowering carbohydrates, but had no e¡ect on lipid content. Carbohydrates were increased while li- pids and protein decreased at the highest salinity (35 Æ 0.9).These results should be taken into consid- eration when evaluating the dietary value of this micro alga for aquaculture. Keywords: Chaetoceros calcitrans ,growth,compo- sition, temperature, salinity, carbon dioxide, live feed Introduction Micro algae are the major food source for manyaqua- tic organisms and the main live feed component in marine hatchery operations because they serve as a natural resource for polyunsaturated fatty acids. The diatom Chaetoceros calcitrans is considered as the most popular strain used in hatcheries, especially for shrimp larvae. This species gives vital energy and organic nutrients for the growth and development of larvae and juveniles (Je¡rey, Brown & Garland1994). Its culture is an important activity, which in£uences the nutritional value of aquatic herbivores (Whyte, Bourne & Hodgson 1989) as well as the economic aspects of their culture (Coutteau & Sorgeloos1992). Very few investigations on the optimal condition for the growth of C . calcitrans are available. Liang (1985) reported the e¡ect of silicate and its optimum level on growth of this diatom. The operation of a cultivation column in airlift mode was proven to be successful and a high growth rate could be achieved even with a lower light intensity than the optimal. The mass production of C . calcitrans through a bioreactor and high growth rate have been reported (Sontaya,Wora- pannee, Sorawit & Prasert 2005). Many speci¢c char- acteristics are thought to in£uence the nutritional value of micro algae, such as cell wall digestibility (Epifanio, Valenti & Turk 1981), cell size and bio- chemical composition (Fernandez-Reiriz, Perez- Camacho, Ferreiro, Blanco, Planas, Campos & Labarta 1989). However, no information is available onthe en-
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This note was uploaded on 01/16/2011 for the course BIO 1107 taught by Professor Devartanian during the Spring '08 term at UGA.

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Growth and proximate composition - Aquaculture Research...

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