Olfactory and taste attractiveness of free amino acids for Persian sturgeon juveniles, Acipenser persicus: a comparison with other acipenserids

Solutions of two from 20 free amino acids tested (L-isomers, 1 mm), alanine and glycine, evoked noticeable food searching behavior in Persian sturgeon A. persicus juveniles (10–13 cm TL). Some of free amino acids such glutamic acid released a weak avoidance response in fish. In contrast to olfaction, 16 and 15 amino acids were positively effective for extraoral and oral taste perception, respectively. Amino acids which significantly decreased fish responses mediated by extraoral taste system (grasps of flavored pellets) or by oral taste system (pellets consumption) as well, were not found. Significant correlation between Persian sturgeon and three other acipenserids in their oral taste perception was absent, but the extraoral taste spectra were significantly correlated between Persian, Russian and stellate sturgeons. The present study demonstrate a weak difference in olfaction between Persian sturgeon and other acipenserids, and high species specificity for taste preferences, especially which are mediated by oral taste system.