RESPIRATION AND NITROGEN-METABOLISM OF ATLANTIC HALIBUT EGGS (HIPPOGLOSSUS-HIPPOGLOSSUS)

Naturally spawned and fertilized eggs of Atlantic halibut, Hippoglossus hippoglossus L., were analysed for protein, free amino acids (FAA), ammonium ions and energy content. The chemical composition was found to be size-dependent but varied little during egg development. Ammonium ions did, however, accumulate during the late embryonic stage, and the trend in FAA content was downward during the same period. Rates of O2 uptake and NH3 excretion followed exponential patterns. A total of 1-mu-mol O2 was consumed and 120 nmol NH3 excreted between the time intervals of fertilization and 1 d post hatch. Derived O:N ratios indicated that the dominant portion of the energy metabolism was lipid- or carbohydrate-based during the mid-development period but switched to FAA as hatch was approached.