Changes of Body Composition During Starvation in Chlorella-extract Fed Ayu

Abstract

The effect of Chlorella-extrac intake on ayu Plecoglossus altivelis was investigated in terms of its physiological merits. Fish of the control group were reared on commercial diet with 6% feed oil for 49 days. In the experimental group, 1% of Chlorella-extract was supplemented to the above diet.
The Chlorella-extract contributed to neither body weight gain nor elevation of feed conversion effciency. The biological measurements and proximate composition of the muscle and viscera were not affected by the supplement. Serological measurements revealed a significant decrease in serum lipid and albumin levels in the experimental group fish. Similarly, analysis of body lipid revealed lipid class changes in visceral lipid, suggesting that Chlorella-extract contributed to the regulation of lipid metabolism. The experimental group exhidbited a tolerance for hypoxic conditions, as well. Upon starvation of the fish for 21 days, body weight loss was much lower in the experimental group. The muscle and visceral lipid levels decreased in the experimental group as compared to the control group.
Chlorella-extract can contribute to the mobilization of a lipid reserve and thus, suppress protein exhaustion due to energy metabolism. The necesssity of ingestion of algae in ayu was discussed in terms of both physiological condition and food habit.