Abstract
The structure-activity relationships of neutral amino acids was examined on fish feeding behavior. It was essential for feeding-stimulating activity that amino acids contain α-hydrogen, and free α-amino and α-carboxyl groups. Active amino acids required a carbon chain with less than five carbons. More than six carbons reduced the effectiveness. Only L-form amino acids have activity. L-Cys, L-Pro, and L-Trp, revealed synergistic responses to active amino acids such as Gly, L-Ala and L-Val.
