The Feeding-stimulatory Effects of Squid Muscle Extracts on the Young Yellowtail Seriola quinqueradiata

Abstract

The feeding-stimulatory effects of extracts of the mantle muscle of squid Todarodes pacificus on the young yellowtail Seriola quinqueradiata were studied by applying the extracts in starch pellets. Pellets containing an extract of the muscle and those containing a synthesized chemical substitute were completely eaten within a short period. However, the stimulatory effectiveness of the natural extract and the synthetic mixture rapidly decreased with decreasing concentration and in both one-tenth dilution resulted in a marked diminution in the number of swallowed pellets. Omission tests for the constituents of the synthetic mixture were performed by dividing them into five groups, A1) amino acids having a stimulatory effect on the taste receptors, A2) those ineffective for the taste receptors, B) betaine, N) nucleotides, and O) organic bases. Omission of A1 individually or together with other groups from the synthetic mixture resulted in a serious reudction in the feeding stimulant activity of the synthetic mixture. A1 showed a high feeding stimulant activity when applied individually. Omission of A2 did not yield any appreciable effect. Omission of N, B or O, all of them were more or less effective for the taste receptors, also decreased the feeding stimulant activity of the synthetic mixture to a small extent. N was rarely accepted when applied individually, but when added to A1enhanced the effectiveness of A1. © 1989, The Japanese Society of Fisheries Science. All rights reserved.