Energy, biochemical substrates and growth in the larval development, metamorphosis and postlarvae of Ostrea edulis (L.)

This study investigates the larval development, metamorphosis and postlarva l stage of O. edulis, evaluating growth, energy acquisition processes and t he role assigned to the different biochemical substrates from a standpoint of both energy and structure. During the premetamorphic stage the highest g rowth rates correspond to organic weight, with a total energy gain of 46.1% . However, during the metamorphosis process the greatest rates correspond t o inorganic weight, with negative growth rates for organic weight, the tota l energy loss being 51.5% of the energy content existing at the beginning o f metamorphosis. In the post-larva greater growth rates are observed in dry weight. In this stage an energetic catabolism continues to be produced, al though much less than in the previous stage (10.7%). The energetic data of larval and post-larval development of O. edulis showed a simultaneous negat ive curvilinear catabolism of lipids, carbohydrates and proteins. With resp ect to ash, adjustment is a positive curvilinear catabolism. With regard to organic weight, a negative linear adjustment is observed. Lipids were the main source of energetic metabolism of O. edulis throughout development, bu t there is also a significant protein catabolism rate. It was shown that th e energy necessary to deposit 1 g of shell during the development of larval and post-larval in O. edulis is 15.04 kJ (3.59 kcal). Shell formation theo ries can explain the destination of at least part of the protein component, which, more than an energetic contribution could be interpreted as a struc tural contribution to shell formation, a process which reaches a high growt h rate (measured in terms of inorganic weight and/or size) during the metam orphosis and post-metamorphosis stages analysed in this work, stages which coincide with increased protein catabolism. (C) 1999 Elsevier Science B.V. All rights reserved.