Palatability of stereoisomers and other amino acid derivatives to fish

Using a behavioral approach, it was shown that stereoisomers and other derivatives of amino acids (Ala, Glu, Gln; 0.1–0.01 М) have different palatability to fish (three-spined stickleback Gasterosteus aculeatus). The palatability of L-α-Ala is higher than of D-α-Ala or L-β-Ala, however, L-Glu and D-Glu equally increase the uptake of agar-agar pellets. L-Glu-Na has no stimulatory effect, probably, due to carnivorous feeding type in the three-spined stickleback. Palatabilities of L-Gln and L-Gln-HCl differ considerably. It is assumed that the influence of the configuration and structure of molecules on the palatability of amino acids to fish, as well as their taste preferences, are species-specific. The diversity of taste properties not only of L-, but also D-isomers of amino acids may matter in choosing adequate food objects in fish. Fish feeding behavior during oral sensory testing of artificial pellets, containing amino acids or their derivatives, obeys two alternative stereotypes, differing in the number of repeated manipulations with pellets and duration of the pellet retention time.