Effect of enriched live feeds on survival and growth rates in larvalKorean rockfish, Sebastes schlegeli Hilgendorf

摘要

High mortality frequently occurs in larval mass production of Korean rockfish, Sebastes schlegeli Hilgendorf, Nutritional deficiencies in live feeds, rotifers and Artemia nauplii, fed to larvae could be a reason, A series of experiments was carried out to evaluate the effect of nutritional enrichment of live feeds by omega -yeast, Spirulina powder and Super Selco(TM) on survival and growth rates in rockfish larvae. Preference of rockfish larvae for the live feeds was determined by analysis of stomach contents. In addition, the effect of green water produced by the use of Chlorella ellipsoidea and Spirulina powder on the growth performance of larvae was evaluated. Larvae fed rotifers nutritionally enriched with Super Selco showed significantly higher survival rates than those fed rotifers enriched with omega -yeast. Larvae fed rotifers that were nutritionally enriched with both Super Selco and Spirulina together exhibited improved growth and survival rates. Larvae fed Artemia nauplii nutritionally enriched with Spirulina powder showed significantly higher survival than larvae fed Artemia nauplii without enrichment. When larvae were fed rotifers, Artemia nauplii or the mixture of rotifers and Artemia nauplii, the second and last group showed significantly higher survival than the first group. Fatty acid composition in live feeds was improved by enrichment of omega -yeast and larvae fed this feed showed higher survival and growth rates compared with larvae fed nonenriched feeds. No positive effect of green water in the tank produced with C, ellipsoidea or Spirulina powder was observed on survival and growth rates for larvae fed nutritionally enriched rotifers with Super Selco and Spirulina powder. However, when the larvae were fed Artemia nauplii that were nutritionally enriched with omega -yeast and Spirulina powder, green water obtained by adding Spirulina powder to the tanks resulted in significantly higher growth rates of larvae than was obtained by adding C. ellipsoidea.