Pilot
evaluation of freeze-dried microalgae in the mass rearing of gilthead
seabream (Sparus aurata) larvae
J. Pedro Cañavate, C. Fernández-Díaz-2001
Aquaculture, 193 (3-4): 257-269
Abstract:
The replacement of live microalgae by freeze-dried
Nannochloropsis gaditana (B3 strain) and Isochrysis galbana (T-ISO strain)
in the mass rearing of larval seabream (Sparus aurata) was studied. Total
substitution of live N. gaditana by freeze-dried cells in 1 m3
larval tanks produced similar growth and survival in larvae reared from
first feeding until day 43 with three different types of rotifer enrichment.
Differences in growth of larvae were only due to the type of enrichment used
to feed rotifers prior to their addition to larval tanks. This was
regardless of the presence of live or freeze-dried N. gaditana in the larval
tanks. Specific growth rate (G) of larvae was significantly enhanced
(G=0.106±0.001; P<0.05) with a commercial enricher compared to N.
gaditana (G=0.099±0.003) as rotifer enricher. Feeding the rotifers with
freeze-dried I. galbana produced the same larval growth rate
(G=0.109±0.002; P>0.05) as the commercial enricher, indicating the high
nutritional value of these algae in a freeze-dried state. Larval survival
was similar in all treatments. Water quality, in terms of dissolved oxygen
and pH, was also similar in the different treatments. Ammonia concentration
was higher (P<0.05) when freeze-dried N. gaditana was added to the larval
tanks, but only during the first 15 days of culture, when no water exchange
was used. Nitrite did not vary (P>0.05) during the first 15 days, but
increased more for live N. gaditana from day 16 onwards. Results of this
study indicate the potential for a complete replacement of live microalgae
by freeze-dried microalgae throughout the whole process of mass rearing
seabream larvae.
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