Abstract
A methanol extract was prepared from the ordinary muscles of nine Amazonian fish specimens caught in May, the end of the rainy season and 11 fish specimens in August, the middle of the dry season of the same year at Manáus where about 1, 200km from the estuary of the Amazon River. Free amino acids and other components of the extract were analyzed. The muscle extracts from Amazonian fish specimens caught in the rainy and dry seasons were generally rich in taurine, creatine, 5'-inosinic acid or inosine, and several inorganic ions. The muscle extract of Pellona castelnaena was rich in taurine and several acidic and neutral amino acids. Relatively higher amounts of trimethylamine oxide were detected in the muscle extracts of Astronotus crassipinnis, Cichla sp., Pellona castelnaena, and Prochilodus nigricans caught in the rainy season and A. crassipinnis, Psectrogester amazonica, and Pellona castelnaena caught in the dry season. A large peak that was presumed to be γ-aminobutyric acid appeared in the chromatogram of amino acid analysis for Metynnis hypsauchen. Amounts of dry matter of the muscle extracts from fish specimens caught in the rainy season were slightly higher than those of the muscle extracts from fish specimens in the dry season.
