GROWTH AND FATTY-ACID COMPOSITION OF PACIFIC OYSTER (CRASSOSTREA-GIGAS) SPAT FED A MICROALGA AND MICROCAPSULES CONTAINING VARYING AMOUNTS OF EICOSAPENTAENOIC AND DOCOSAHEXAENOIC ACID
J. Knauer et Pc. Southgate, GROWTH AND FATTY-ACID COMPOSITION OF PACIFIC OYSTER (CRASSOSTREA-GIGAS) SPAT FED A MICROALGA AND MICROCAPSULES CONTAINING VARYING AMOUNTS OF EICOSAPENTAENOIC AND DOCOSAHEXAENOIC ACID, Journal of shellfish research, 16(2), 1997, pp. 447-453
Pacific oyster (Crassostrea gigas) spat were fed for 28 days on either
a 100% ration of the microalga Dunaliella tertiolecta, which lacks fa
tty acids greater than C-18, or an 80% ration of D. tertiolecta and 20
% gelatin-acacia microcapsules (GAM). GAM contained corn oil alone or
corn oil supplemented with varying amounts of either eicosapentaenoic
acid (20:5n-3, EPA), docosahexaenoic acid (22:6n-3, DHA), or combinati
ons of the two. GAM containing either corn oil, corn oil containing up
to 0.16% EPA (dry weight of GAM), 0.63% DHA, or 0.32% of an EPA/DHA m
ixture did not improve shell length, dry weight, or ash-free dry weigh
t (AFDW) of spat compared with spat fed D. tertiolecta alone. However,
GAM containing 0.30 and 0.50% EPA resulted in spat with significantly
higher AFDW than spat fed either D. tertiolecta alone or D. tertiolec
ta plus GAM containing corn oil. There was a significant positive corr
elation between the level of EPA present in GAM and AFDW of spat. The
results suggested that spat growth may improve further at levels of di
etary EPA higher than those used in this study. The fatty acid profile
of spat generally reflected that of the diet after 28 days. However,
the increase in dietary levels of both EPA and DHA were not reflected
and unfed spat selectively retained EPA and DHA.