Evaluation of crystalline amino acids, betaine and AMP as food attractants of the giant tiger prawn (Penaeus monodon)

Laboratory observations of substrate probing by the chelate walking legs (chelipeds), antennular flicking rate and maxilliped activity of the prawn Penaeus monodon were used to evaluate various chemicals at seven different concentrations between 10(-1) M and 10(-7) M as feeding stimulants. Exposure to amino acids (alanine, arginine, glutamine, glycine, isoleucine: serine and taurine) and betaine resulted in higher rates of substrate probing, antennular flicking and maxilliped activity in P. monodon at higher pipette concentrations (> 10(-2 M)) than at lower concentrations. Least response occurred in prawns which were exposed to nucleotide, adenosine 5'-monophosphate. Glutamine, betaine and taurine were the most effective single compounds tested, and stimulated significantly higher activities (P < 0.05) in prawns at concentrations above 10(-6) M than did controls (seawater only). An equimolar mixture of amino acids and betaine was also found to be an effective stimulant to P. monodon at concentrations above 10(-6) M and continued to elicit search responses in prawns at concentrations lower than that of any of the single chemicals. Such a strong response is consistent with synergistic interactions of the mixtures. All four molt stages tested (C, D-0, D-1, D-2) were equally responsive to food attractants.