Identification of Feeding Stimulants for Marbled Rockfish

Abstract

Feeding stimulants for the marbled rockfish Sebasticus marmoratus were identfied by the omission test uding the synthetic extract of krill Euphausia pacifica. The fish were fed on a purifiedcasein diet supplemented with constituents of the extract for 6 days.
The feeding stimulant activity was evaluated by the daily feeding rate. The nucleotide fraction of the extract was the most effective, followed by the amino acid fraction which showed a littel activity. Inosine had the highest activity among all constituents of the extract. With increasing supplementary level to the diet, amino acids such as L-alanine, L-methionine, L-serine and L-proline and nucleotides such as adenosine-5'-diphosphate, adenosine-5'-monophosphate and inosine-5'-monophosphate became positive. When inosine together with, L-alanine, L-methionine, L-serine and L-proline was supplemented to the diet, its activity for the fish was remarkably improved, becoming to the synthetic extract.