IDENTIFICATION OF FEEDING STIMULANTS FOR TIGER PUFFER

Feeding stimulants for the tiger puffer Takifugu rubripes were identif ied by omission test using the synthetic clam Tapes japonicus extract, based on a daily feeding rate for casein diet with each test solution . The amino acid fraction showed remarkably higher feeding stimulant a ctivity than those of nucleotide and other chemical fractions in the e xtract. Among 18 chemicals in the amino acid fraction, L-serine, L-asp artic acid, glycine, and L-alanine showed slightly higher activity tha n deionized water, but lower than the amino acid fraction. The mixture of the above four amino acids plus betaine showed a markedly higher f eeding stimulant activity than that of the synthetic extract, indicati ng the synergistic effect. The positive supplement level of the four a mino acids plus betaine was found to be that corresponding. to 100 g o f clam muscle per 100 g of casein diet.