ＤＨＡ含量が異なるワムシを摂餌したブリ仔稚魚のアルテミア摂餌期におけるＤＨＡ要求

Abstract

A feeding experiment was conducted to examine the effect of different docosahexaenoic acid (DHA) content in rotifers on the DHA requirement of larval yellowtail Seriola quinqueradiata during Artemia feeding stages. Rotifers enriched with freeze-dried shark eggs (HR) or Nannochloropsis (LR) having different levels of DHA were given to larvae for 23 days. Each lot of larvae was then divided into three groups, and each group was fed Artemia containing different levels of DHA; 0%, 1.6% and 2.6%, respectively, for 16 days.Both survival and vitality of larvae during Artemia feeding stages were affected by the DHA levels in rotifers at the start of feeding. It was found that as DHA content in rotifers increased, the DHA requirement of larvae during Artemia feeding stages decreased from 2.6 to 1.6%. When larvae were fed rotifers containing 1.3% DHA followed by Artemia containing 1.6% or 2.6% DHA, healthy larvae were obtained. The survival and vitality of larvae fed on rotifers having a low level of DHA improved by feeding them with Artemia containing 2.6% DHA.The results indicate that the DHA content in rotifers influences the DHA requirement of larval yellowtail during the Artemia feeding stages.