Olfaction and gustation in acipenseridae, with special references to the siberian sturgeon

Abstract

In sturgeons our knowledge about chemosensory systems is restricted by olfaction and gustation which are well developed in these fish. Data about the common chemical sense in Acipenseriformes is totally absent up to now. Basic morphology of olfactory organ is nearly identical among genera and species. It is paired structure and lies on the dorsal side of rostrum. Cuplike olfactory rosette comprises radially arranged primary lamellae (up to several dozens). Primary lamellae have secondary lamellae which vary in number. Olfactory sensory neurons are presented by ciliated, microvillous and crypt receptor cells. Olfaction is the main distant sensory system in sturgeons and plays a significant role in feeding, reproduction and, as supposed, homing. Ability to respond to food odour appears just after the beginning of exogenous feeding. Gustatory system is presented by two distinct subsystems, oral and extraoral. Taste buds are situated not only within the oral cavity, pharynx and gills but also on the lips and barbels and are absent in the rostrum and fins and over the entire trunk surface. Morphology of oral and extraoral taste buds is similar. Organic and inorganic chemicals and food extracts are highly effective taste stimuli. Oral gustatory system has a narrower spectrum of effective substances than extraoral one and has a higher specificity. Taste buds develop later than the olfactory organ. Extraoral taste buds appear first, then come oral taste buds and then larvae start feeding. The significance of basic knowledge in sturgeon olfaction and gustation for aquaculture is emphasised.