Preliminary Experiment on the Requirement of Larval Redlip Mullet for Essential Fatty Acids, and the Supplemental Effect of Nannochloropsis to Rearing Water

Abstract

A feeding experiment for redlip mullet larvae (4.58 ±0.25 mm TL) on the EFA requirement was conducted by using rotifers enriched with ethyl esters of four kinds of fatty acids: linoleic acid, LA; linolenic acid, LNA; eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA. Larvae receiving rotifers enriched with LA and LNA showed typical symptoms of EFA deficiency syndromes, and obtained poor growth and high mortality. On the other hand, the larvae receiving rotifers enriched with EPA and/or DHA showed better growth, activity, and survival rates. These results suggested that the redlip mullet larvae required n-3HUFA like EPA and DHA as their essential fatty acids. Also, the supplemental effect of unicellular alga Nannochloropsis sp. to rearing water was investigated from the view point of EFA requirement. The n-3HUFA content in rotifer cultured with Nannochloropsis decreased linearly after they transferred into sea water. However, when 40–50 x 104 cells/m/ of Nannochloropsis was introduced to a rearing tank, the n-3HUFA content in rotifer remained without decreasing for 6 hours. The larvae reared in the tank with Nannochloropsis supplement showed better growth than those of non- or fewer-supplement groups. © 1995, The Japanese Society of Fisheries Science. All rights reserved.