Abstract
The present investigation was conducted to identify the feeding stimulants for jack mackerel Trachurus japonicus by a bioassay method using the synthetic extract, based upon analysis of jack mackerel muscle. The purified casein basal diet flavored with the synthetic extract was readily ingested by the jack mackerel, but the unflavored diet was not ingested at all. By a series of omission tests with the synthetic extract, the nucleotides group was most stimulatory in the three major groups (amino acids, nucleotides, and other bases) examined. Of the nucleotides examined, only inosine-5'-monophosphate (IMP) was highly stimulatory, but its activity was interfered with the presence of inosine, adenosine-5'-diphosphate or creatine. From these results, we concluded that IMP is the most effective feeding stimulant for jack mackerel in its muscle extract.
