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

This study investigates the larval development, metamorphosis and postlarval stage of O. edulis, evaluating growth, energy acquisition processes and the role assigned to the different biochemical substrates from a standpoint of both energy and structure. During the premetamorphic stage the highest growth rates correspond to organic weight, with a total energy gain of 46.1%. However, during the metamorphosis process the greatest rates correspond to inorganic weight, with negative growth rates for organic weight, the total energy loss being 51.5% of the energy content existing at the beginning of metamorphosis. In the post-larva greater growth rates are observed in dry weight. In this stage an energetic catabolism continues to be produced, although much less than in the previous stage (10.7%). The energetic data of larval and post-larval development of O. edulis showed a simultaneous negative curvilinear catabolism of lipids, carbohydrates and proteins. With respect 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, but there is also a significant protein catabolism rate. It was shown that the 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 theories can explain the destination of at least part of the protein component, which, more than an energetic contribution could be interpreted as a structural contribution to shell formation, a process which reaches a high growth rate (measured in terms of inorganic weight and/or size) during the metamorphosis and post-metamorphosis stages analysed in this work, stages which coincide with increased protein catabolism.