Optimization of feeding rate
for hatchery-produced juvenile gilthead sea bream Sparus aurata
A. Mihelakakis, C. Tsolkas, Y. Yoshimatsu-2002 AU
Journal of the World Aquaculture Society, 33(2):
169-175 (from Current Contents)
Abstract :
A 61-d growth trial (five 11-d feeding periods) was
conducted to determine the effects of feeding rate on growth, feed
utilization, morphology, and body composition of the gilthead sea bream
Sparus aurata. Gilthead sea bream juveniles with an average initial body
weight of 3 g were fed a commercial diet (51% crude protein, 11% crude fat)
at rates of 0.5, 1.0, 1.5, 2.0, 2.5, or 3.0% of their body weight (BW) per
day in two equal meals. Water temperature was approximately 21.4°C
throughout the experiment. Each ration was administered to triplicate groups
of 60 fish, with ration readjusted every 11 d. Growth rate was measured as
specific growth rate (SGR). Survival rate and coefficient of variation did
not differ significantly among the groups fed different rates. Body weight,
condition factor, and hepatosomatic and viscerosomatic indices displayed
significant increases with increasing feeding rate from 0.5 to 3.0% BW/d.
Fish fed 0.5% BW/d had significantly higher moisture and ash and lower
protein contents than those fed at higher rates. Moisture and protein
contents were not significantly different for fish fed at the highest
feeding rates (2.0, 2.5, and 3.0% BW/d). Lipid contents increased
significantly with increasing feeding rate from 0.5 to 3.0% BW/d. The SGR
showed a curvilinear significant increase when the feeding rate was
increased from 0.5 to 3.0% BW/d. Feed efficiency (FE) increased
significantly to a maximum value with increasing feeding rate from 0.5 to
2.0% BW/d and decreased significantly with increasing feeding rate from 2.5
to 3.0% BW/d. Based on the data obtained, feeding rates of 2.3% and 0.6%
BW/d are recommended as optimum and maintenance rations, respectively.
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