Gustatory Characteristics of Carboxylic Acids for Ninespine Stickleback Pungitius pungitius

Abstract

The palatability of 18 carboxylic acids and ascorbic acid (0.1 M) is determined in ninespine stickleback Pungitius pungitius. It is found out that all acids are effective taste stimuli causing an aversive food reaction in fish. Twelve acids have the strongest effect (adipic, valeric, malic, oxalic, fumaric, succinic, Na-cholic, butyric, propionic, acetic, сaproic, and ascorbic acids), and they cause the fish to cease the consumption of agar–agar pellets completely. The relationship between the palatability of carboxylic acids and their molecular weight, as well as for the pH of water solutions and the structural features of the molecule, is not revealed. It is found that the feeding behavior of individuals of ninespine stickleback has changed significantly in regard to some substances (citric acid) after 8 months from the previous experiment. The possible causes of these changes are discussed.