EVOLUTION OF BIOMETRIC INDEXES AND PLASMA METABOLITES DURING PROLONGED STARVATION IN EUROPEAN SEA BASS (DICENTRARCHUS-LABRAX, L)

Taking as criteria plasmatic urea profiles, and percentage losses over time in weight and in condition factor, the process of starvation (up to 150 days) in European sea bass (Dicentrarchus labrax) divides into two phases. In the first phase (up to 50 days), there is no variation in the concentration of urea, the percentage losses in condition fact or are greater than those in weight, intestinal fats are exhausted, pr emature involution of gonadal tissue occurs, there is no variation in the chemical composition of white muscle, and proteinaemia decreases. In the second phase, there is an increase of 237% in the concentration of urea, percentage losses in weight predominate over those in the co ndition factor, the moisture in white muscle increases, while ash redu ces, and proteinaemia returns to its initial values. Of all the plasma free amino acids measured, only Arginine falls dramatically during th e onset of starvation and, after stabilizing, there is the significant increase in urea mentioned above. Plasma concentration of NH3 remaine d constant throughout the experimental period. Significant variations in plasmatic Alanine were not detected. Concentrations of plasma Tauri ne remained high during the whole of the second phase. (C) 1997 Elsevi er Science Inc.