LYSINE REQUIREMENT OF JUVENILE JAPANESE FLOUNDER PARALICHTHYS-OLIVACEUS AND JUVENILE RED-SEA BREAM PAGRUS-MAJOR

The lysine requirement of juvenile Japanese flounder (3.0 g initial we ight) and red sea bream (1.7 g initial weight) was estimated by feedin g six semi-moist diets (45-48% crude protein on dry basis) containing graded levels of lysine hydrogen chloride in replacement of sodium glu tamate. Most of the amino acids in the diets were provided by zein, fi sh meal and gelatin. In addition, free amino acids were added to ensur e that the requirements for the essential amino acids, other than lysi ne, were met. Specific growth rate, feed efficiency, and nitrogen rete ntion data were analyzed by non-linear regression using the broken-lin e model to obtain the lysine requirement estimates for Japanese flound er of 3.3, 4.2 and 4.6% of dietary protein, respectively, and 3.6, 4.3 , and 4.4% of dietary protein for red sea bream. Estimates of the requ irements for the other essential amino acids were made based on A/E ra tios of the whole-body amino acid profile. (C) 1998 Elsevier Science B .V.