Effects of varying Artemia
enrichment on growth and survival of juvenile seahorses, Hippocampus
abdominalis
C.M.C. Woods-2003
Aquaculture, 220(1-4): 537-548
Abstract:
Seahorses are the focus of recent aquaculture
ventures in a variety of countries. Many of these ventures utilise enriched
live Artemia (to varying degrees) to feed their seahorses. Given the
range of commercially available enrichment products that can be used to
enrich Artemia, it is imperative to determine which of these may
promote the best growth and survival in seahorses, as well as being most
cost-effective. This investigation tested the effects on juvenile seahorse (Hippocampus
abdominalis Leeson, 1827) growth and survival through enriching Artemia
with three commercial enrichment products: Super SelcoŽ, DHA Protein SelcoŽ
and Algamac-3050. These were tested against a low-cost Artemia
on-growing mixture used in this instance as an enrichment (90% Eyre
Peninsula Aquaculture brine shrimp food (EPABSF)/10% spirulina).
After 3 months, there was a significant difference in
juvenile length between the enrichment treatments, with juveniles in the DHA
Protein SelcoŽ and Algamac-3050 treatment longer than juveniles in the
Super SelcoŽ treatment, but not longer than juveniles in the
EPABSF/spirulina treatment. There was also a significant difference in
juvenile wet weights between the treatments, with juveniles in the Super
SelcoŽ treatment weighing significantly less than juveniles in the other
three treatments.
In terms of condition factor (CF), there was a slight
significant difference between the treatments, with juveniles in the DHA
Protein SelcoŽ and EPABSF/spirulina treatment having higher CFs than
juveniles in the Super SelcoŽ treatment, but not the Algamac-3050
treatment. Mean daily specific growth rate (SGR) for Super SelcoŽ was lower
than the other three treatments. There was no effect of enrichment treatment
on seahorse survival with 100% survival in all four treatments.
Fatty acid analysis revealed marked differences in
the Artemia enriched with the various enrichment products. Super
SelcoŽ- and Algamac-3050-enriched Artemia had the highest percentage
of docosahexanoic acid (DHA), 22:6(n-3), while Super SelcoŽ-enriched
Artemia had the highest percentage of eicosapentaenoic acid (EPA),
20:5(n-3). EPABSF/spirulina-enriched Artemia had the highest
percentages of C18 fatty acids. Percentage of polyunsaturated fatty acids
(PUFA) and n-3 PUFAs were highest in Super SelcoŽ- and
Algamac-3050-enriched Artemia. Proximate analysis revealed little
difference among all four enrichment treatments in terms of protein, fat and
carbohydrate levels.
The results from this experiment demonstrate that
when culturing H. abdominalis, all three commercial enrichment
products produce good seahorse growth and excellent survival. However, on a
cost/benefit basis, all three commercial products were outperformed by the
cheaper Artemia on-growing mixture (EPABSF/spirulina).