15 SEPTEMBER 1999
ESSENTIAL FATTY ACIDS IN PLANKTON FROM COLD OCEAN COASTAL ENVIRONMENTS
S.M. Budge, C.C. Parrish, R.J. Thompson, C.H. McKenzie-1998
Bulletin of the Aquaculture Association of Canada, 98-2 (contributing papers Aquaculture Canada '98): 56-58
Abstract:
The fatty acid nutritional requirements of marine finfish and shellfish are of utmost importance. The long-chain polyunsaturated fatty acids (PUFA), arachadonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are essential for animal growth and survival. Insufficient amounts of these acids in the diet have a variety of deleterious effects, including reduced feeding efficiencies, liver damage and behavioural changes. Studies have suggested that for broodstock conditioning optimum levels of (omega3/omega6 PUFA in finfish diets are in the range of 5:1 to 10:1, while the recommended ratio of the specific fatty acids DHA/EPA is 2:1. In adult bivalves, more appropriate ratios seem to be 5:1 to 15:1 and 1:1, respectively, while in larvae the correct ratio of DHA/EPA may be as low as 1:2. Such requirements are often overlooked when establishing bivalve aquaculture sites in the natural environment. A former aquaculture site in Notre Dame Bay, Newfoundland, was investigated to determine typical fatty acid compositions of plankton. The quality of plankton-produced fatty acids in the natural environment fluctuates both spatially and temporally and we have found that the ratios in plankton (> 10 micro m) in this area have a variety of values. PUFA levels in plankton were high, ranging from 33 to 57% of total fatty acids with an average of 44%. Ratios of (omega3/omega6 PUFA varied from 4 to 22 with an average of 12, while the ratio of DHA/EPA ranged from 0.1 to 2.4 with an average of 1.0. The average values of these ratios compared well with the corresponding values found in mussels (Mytilus edulis) in Notre Dame Bay.
(Department of Chemistry, Memorial University of Newfoundland, St. John's, NF, Canada A1B 3X7)