Feeding attraction activities of amino acids and lipids for juvenile yellowtail.

Abstract

Fractions of basic, neutral and acidic amino acids, and of neutral, phospho- and glyco-lipids were prepared from the amino acid- and the lipid-extracts obtained from the mid-gut gland of squid Todarodes pacificus. The basic amino acid- and the phospholipid-fractions induced a high behavioral feeding attraction activity for juvenile yellowtail Seriola quinqueradiata and the neutral amino acid- and the glycolipid-fractions did bring about a low activity.Of twenty-six authentic L- and DL-amino acids, the activities were found in histidine, arginine, lysine and ornithine among the basic amino acids. Especially, histidine and arginine strikingly induced an attraction behavior in the fish. In the neutral amino acids, glycine, valine, threonine, methionine and cystine were involved in the attraction, specially glycine and threonine showing high activity. In the acidic amino acids, asparatic acid and glutamic acid didn't show an activity, while their amides did. Both L-histidine and L-threonine elicited the attraction in contrast to D-types which showed little effects.Of thirty authentic lipids, the activities were high in many kinds of phospholipids. Among the other lipids, however, only palmitic acid and stearic acid, monostearin, and ceramide were effective.The threshold values were estimated to be 5×10-7 M and 6×10-8 M for L-histidine and egglecithin, respectively.