STIMULATORY EFFECTIVENESS OF AMINO-ACIDS ON THE OLFACTORY RESPONSE IN AN ALGIVOROUS MARINE TELEOST, THE RABBITFISH SIGANUS-FUSCESCENS HOUTTUYN

The detection of threshold concentrations and relative stimulatory effectiveness (RSE) for 19 amino acids were studied by olfactory bulbar electroencephalogram (EEG) in the algivorous rabbitfish. The threshold concentrations for 19 amino acids ranged from 10−10 to 10−5 M. l‐Alanine was the most effective amino acid, and the threshold concentration was estimated to be from 10−10 to 10−9M. These results were compared with the olfactory response in herbivorous and carnivorous fishes previously reported. The comparison of RSE for rabbitfish with those for other fishes showed correlation coefficients ranging from r= 0.97 to r= 0.50, but high similarities did not correspond with difference in feeding habits for herbivores and carnivores. The role of amino acids in fish chemosensory behaviour and the olfactory response of the rabbitfish was compared with the gustatory response reported previously. It was found that l‐serine was the most potent stimulant in both chemoreceptors, l‐proline and l‐glutaminic acid were the most potent gustatory stimulants, and l‐alanine, l‐glutamine, l‐arginine and l‐lysine were the most potent olfactory stimulants. Copyright © 1992, Wiley Blackwell. All rights reserved