Dynamics of fatty acids in the larval development, metamorphosis and post-metamorphosis of Ostrea edulis (L.)

We analysed the composition of fatty acids during the larval development of Ostrea edulis in view of the role played by essential fatty acids (i.e. 20 :5n-3 and 22:6n-3) during the three most important stages in the developmen t, with particular emphasis on metamorphosis, of this mollusc. In the first stage (larval period) all fatty acids increase. During metamorphosis (50% eyed, 72 h) there is still an increase but smaller than during the larval p eriod, for all major Fatty acids with the exception of polienoic, n-3PUFAs (polyunsaturated fatty acid) and C20 and C22 non-methylene-interrupted dien oic (NMID). The juvenile shows the highest gain for all the main fatty acid s. Changes in the PUFAs composition were marked by an increase in the 22:6n -3/20:5n-3 ratio during the period of larval development, followed by a dec rease in this ratio until 6 days after the onset of metamorphosis, and fina lly a further increase during the post-metamorphosis stage. The losses in 2 2:6n-3 for the period between the end of metamorphosis and 6 days after its onset would seem to indicate a specific function for each of these two fat ty acids, with a structural role for 22:6n-3 and an energy-providing role f or 20:5n-3. (C) 1999 Elsevier Science Inc. All rights reserved.