| Popis: |
Tests for food efficiency and characteristics of chilled and frozen Nannochloropsis sp. (marineChlorella) were conducted in order to know the applicability of preserved food in massculture ofrotifer, Brachionus plicatilis, in consideration of the maintenance of the water quality. Chilled algawas prepared through concentration and preservation by chilling at 3°C. While frozen food wasprepared by freezing of the concentrated alga at -25°C within the period of 20 minutes. Bothtypes of food were preserved at the respective temperature for a month before the use in theexperiment.As to food efficiency of preserved algae, no significant difference was observed on the populationgrowth of rotifers fed on both fresh and preserved algae. As to activity of preserved alga, chilledalga represented the same growth ability of fresh one under high light intensity. However, at lowlight intensity of 150 lx, growth was not observed. Frozen alga showed 3 times higher exudation oforganic nitrogen from cell, in comparison with chilled alga. |
