テトラセルミスで培養したシオミズッボワムシのマグイ仔稚魚に対する餌料価値

抄録

A minute alga Tetraselmis tetrathele is one of the food organisms which have been intoroduced into Japan recently. T. tetrathele was well evaluated already as a substitute for Chlorella because of the high food value for a rotifer Brachionus plicatilis and its eurythermal characteristic beside the tolerance to high temperature. But, the dietary value of the rotifer cultured with T. tetrathele remains unknown.
Tje doetary value of rotifers cultured with T. Tetrathele (TR) or both T. tetrathele and Chlorella sp. (TCR) was compared with those cultured with Chlorella (CR) by feeding these various rotifers to larval red seabream for 17 days. The rotifers enriched by Chlorella (12-24 hours) after culturing with T. tetrathele (TR-C) was also given to the larvae. The survival rate and the total length of fish fed TR was better than those receiving CR (75.6 and 83.5% vs. 65.1 and 75.6% in survival rate, 7.5 and 8.1 mm vs. 6.5 and 6.9 mm in average T. L.), although there were no significant dif-ferences in body weight. Furthermore, the survival rate and the growth of fish fed TCR or TR-C were superior to the former, i. e., 68.0-80.1% and 8.7-8.8mm in TCR, 74.4-81.1% and 8.5-9.1mm in TR-C. There were no differences in proximate composition of the rotifers with various feeds and treatment. The difference in survival rate and growth among the larvae with different feeds might be due to the difference in the conten of ω3 HUFA. Thepercentage of ω3 HUFA in the lipids of TR, TCR, TR-C, and CR were 12.4%, 20.9%, 20.4-25.4%, and 23.9%, respectively. The amount of ω3 HUFA in the rotifers cultured with T. tetrathele was not enough, but might be the minimum (0.3% in rotifer). The influence of 18:3ω3 included in the rotifer at high per-centage (22.4%) should be studied in future works.