Growth Responses of Cherry Salmon Oncorhynchus masou and Amago Salmon O. rhodurus Fry Fed Purified Casein Diets Supplemented with Amino Acids

Abstract

Feeding experiments were carried out to examine the supplemental effect of crystalline amino acids to casein diets on the growth of cherry salmon Oncorhynchus masou and amago salmon O. rhodurs fry. The essential amino acid patterns of eyed egg and whole body protein of cherry salmon were used as references. The following four diets were given to both groups for six weeks; a casein diet without crystalline amino acid (Diet 1), a casein diet supplemented with crystalline amino acids to simulate the essential amino acid ratio (A/E ratio) of the eyed egg protein (Diet 2), a casein diet supplemented with crystalline amino acids to simulate the A/E ratio of the whole body protein (Diet 3), and a white fish meal diet (Diet 4). Both species showed essentially the same responses to the dietary treatments and their growth responses were as follows Diet 3>Diet 2>Diet 1>Diet 4. The groups fed on Diet 3 showed significantly higher daily growth rates than those fed on Diet 1, whereas daily growth rates between Diet 2 group and Diet 1 group were not significantly different. The highest feed effciency and protein effciency ratio were obtained in the groups fed on Diet 3. Fishes fed on Diet 4 showed the highest daily feed consumption rates, but the daily growth rates and the feed effciencies were the poorest compared to all the other dietary groups.