Studies on the chemical nature of feeding stimulants for rainbow trout, Salmo gairdneri Richardson

Rainbow trout trained to operate a demand feeder showed a marked preference for a diet flavoured with a synthetic mixture of chemicals over the unfavoured diet. The gustatory feeding stimulant activity resided in the amino acid fraction and was stereospeciflc for the L-forms. Certain mixtures of L-amino acids were stimulatory, while the individual components of the mixtures were inactive or repellent.