Effects of Amino Acids on Pecking Behavior of the Rose Bitterling Rhodeus ocellatus ocellatus.

Abstract

Amino acids function as feeding stimulants in many kinds of fish. In this study, we examined whether the feeding behavior in both male and female rose bitterling Rhodeus ocellatus ocellatus is induced by amino acids. Only the rose bitterling was attracted to a dialysis tube containing an amino acid solution, and it displayed a pecking behavior toward the tube. This pecking was not actually feeding behavior, because the fish did not open their mouths and their movement was very slow and gentle. But female fish did not show any pecking behavior. There is thus the possibility that this male-specific behavior may be sexual. 10 out of 20 amino acids induced male pecking behavior, the order of intensity being L-cysteine >L-serine>L- alanine>glycine>L-lysine, as determined by competitive assay.