Collected reprints: Abstract 2979
Collected reprints
Abstract
Tzovenis, I.; De Pauw, N.; Sorgeloos, P. (1997). Effect of different light regimes on the docosahexaenoic acid (DHA) content of Isochrysis aff. galbana (clone T-ISO). Aquaculture International 5: 489-507
The culture of Isochrysis aff. galbana Green (T-ISO) in hatcheries is promoted for its high docosahexaenoic acid (DHA) content which favours the successful rearing of aquatic larvae. In this paper we identified the need for well-defined culture conditions of microalgae if sufficient DHA content is the final goal. Using photoperiods of 24:0h, 12:12h and 16:8h L/D combined with photon flux densities (PFD's) of 110, 220 and 460 µE m-2 s-1, batch cultures of T-ISO were sampled for DHA content in the exponential as well as the post-exponential (light-limited) growth phase. The various light regimes resulted in differences of DHA content of T-ISO revealing influences and strong interactions among the three variables studied. For fast and economic production of T-ISO cells rich in DHA it is recommended to harvest batch cultures at the end of the exponential phase using high photon flux densities (PFD's) under 12:12 h L/D cycles. The same regime or lower PFD under 24:0 h L/D seem to be sufficient for a continuous culture optimization scheme. In any case a strict following of culture protocols is very important since there is evidence for coexistence of different clones within the parental cultures leading to different results depending on which one prevails.
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