No efflux of free amino acids from yolk-sac larvae of Atlantic halibut ( Hippoglossus hippoglossus L.)

Abstract

The efflux for free amino acids (FAA) was investigated in groups of 2–6 yolk-sac larvae of Atlantic halibut ( Hippoglossus hippoglossus L.) incubated for 116 or 94 h in about 11 ml of 2 μm filtered sea-water containing a broad spectrum antibiotic (Nitrofurazolidon, 0.5 ppm). During incubation the larval pool of FAA declined by about 300 nmol·ind −1 but there was no concomitant increase in the FAA concentration of the incubation water which remained at about 0.3 μM. If the recorded decline in the larval FAA pool was due to efflux to the surrounding medium values of about 65–190 μM. in the incubation water would have been expected. The results suggest that the decline in the larval FAA pool is not due to an efflux, but rather derives from metabolic transformations within the embryo.