Reduction of goldfish olfaction when exposed to anionic detergent

Olfaction of goldfish was examined when fish was exposed to anionic detergent- sodium dodecyl benzene sulfonate through electrophysiological and aquarium experiments. The electro-olfactogram (EOG) technique was used to record the responses of goldfish to food stimulus when exposed to different detergent concentrations. A bipolar Ag-AgCl wire electrode was placed lightly on olfactory bulb, which was exposed by opening the roof of the skull. The stimulus, which is a mixture of food extract and different detergent concentrations, was delivered to the olfactory rosette using a stimulus delivery system. Taste responses of fish showed that the ability of the fish to detect food was significantly diminished during exposure to 100 ppm detergent. However, olfaction was subsequently restored after 60 min washing with artificial freshwater. Electrophysiological responses were complemented with aquarium behavioral studies. The amount of time the fish exhibited feeding patterns was determined using the following scores: mouth opening and snapping at the surface, biting and snapping against the bottom or walls, and vertical posture. Results showed that the ability of the fish to detect food extracts was reduced when exposed to detergent with 50 ppm concentrations or higher. Studies such are these provide information on the effects of pollutants (e.g. detergent) on the biology and ecology of aquatic organisms, like feeding, growth and reproduction.