Tryptophan Requirement of Chum Salmon Fry

Abstract

Quantitative tryptophan requirement of chum salmon Oncorhynchus keta fry was determined by feeding purified diets containing crystalline L-amino acids and 5% casein as nitrogen sources for 4 weeks. The basal diet was isonitrogenously supplemented with graded levels (0.05, 0.08, 0. 16, 0.24, 0.32, 0.40, 0.48 and 0.56% in diet) of tryptophan by adjusting the level of alanine. Based on the growth data, the requirement for tryptophan was found to be 0.29% of diet and 0.73 of dietary protein. Scoliosis or lordoscoliosis of the trunk were observed in 53-84% of the fish which were fed with the diet containing less than 0.16% of the supplemental tryptophan.