COMPARISON OF GROWTH, FEED-EFFICIENCY, AND CHEMICAL-COMPOSITION OF JUVENILE FLOUNDER FED LIVE MYSIDS AND FORMULA FEED UNDER LABORATORY CONDITIONS

The objectives of this study is to compare growth, feed efficiency, an d chemical composition of juvenile flounder Paralichthys olivaceus fed live mysids and formula feed under laboratory conditions. Four rearin g experiments (9 to 10 days), using four different size fish, were con ducted at four different constant temperatures (13, 16, 19, and 22 deg rees C). Temperatures used in the present study were chosen according to those at the nursery ground in Wakasa Bay during spring and early s ummer. Fish were fed live mysids or formula feed during experiments. F ish fed live mysids showed always higher growth rates in length (1.04- 2.09 times in expts. 13) and weight (1.14-2.65 times in expts. 3 and 4 ), better feed efficiency (1.56-4.34 times in expts. 3 and 4) than tho se fed formula feed at any temperatures. Chemical compositions (proxim ate composition and fatty acid profile) of fish at the end of experime nts reflected those of diets, and those of fish fed live mysids were n early the same as those of wild juveniles.