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Abstract
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The marine fish larvae mostly rely on livefeed, with certain nutritional deficiencies such as poor long chain fatty
acids, in spite of recent progress in developing artificial feed. Thus, the present experiment was conducted to
evaluate a 30-day dietary effects of enriched rotifer (Brachionus rotundiformis) and Artemia nauplii (Artemia
franciscana) with docosahexaenoic acid (DHA) on performance of yellowtail sea bream (Acanthopagrus latus)
larvae. For this purpose, 60,000 larvae from wild broodstocks were stocked in 12 tanks (50 larvae/L) supplied
with green water (0.5 ×106 cell/ml Nannochloropsis. sp). The rotifer and Artemia were enriched with four
experimental emulsions contained four levels of DHA including very low (6 %, DHA-VL), low (12 %, DHA-L),
medium (24 %, DHA-M) and high (37.8 %, DHA-H). Larvae were fed with rotifers from day 2–20 post hatch
(DPH) and Artemia metanauplii (Instar-II, from 16 to 30 DPH). After the 30-day dietary trial, survival rate and
growth performance of larvae were found not affected by different levels of DHA (P > 0.05). The activity of
digestive enzymes including total proteases, lipase, amylase, alkaline phosphatase, and leucine-alanine peptidase
showed some fluctuations among the experimental groups. However, in the most of the sampling intervals,
except for protease activity, the activity of digestive enzymes did not change significantly among the experimental
groups. The n–3 polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and DHA, were the
highest in the whole body of larvae from DHA-M treatment. The DHA/EPA ratio in the whole body of larvae was
significantly increased with increasing DHA level (P < 0.05). Based on our findings, very low levels of DHA is
enough for supporting normal growth, survival and metamorphosis in developing A. latus larvae up to 30 days
post hatching.
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