Reproductive conditioning of Chilean scallop (Argopecten purpuratus) and the Pacific oyster (Crassostrea gigas): effects of enriched diets

The quality of diet fed to bivalve broodstock during reproductive conditioning directly affects growth and survival of their larval and postlarval progeny. The objective of the present study was to improve the quality of larval production in the Chilean scallop (Argopecten purpuratus) and the Pacific oyster (Crassostrea gigas) by testing of the effects of different experimentally enriched diets on the conditioning and early development of progeny under laboratory conditions. The diets used included protein-rich microalgae and mixtures of microalgae and lipid emulsions. Quality of D-larvae, pediveligers, and 1-mm postlarvae from the variously fed broodstock was measured to evaluate each diet as indicators of growth and survival of the early life stages. Biochemical analyses were carried out on eggs and larvae to determine the effects of the different diets on these parameters. The main results for the scallops and oysters were that a conditioning diet containing algae rich in protein improved larval growth and survival. This effect did not, however, extend past metamorphosis. Also, the best conditioning diet increased the lipid content of the eggs, as well as the protein content of the D-larvae, although the mechanism for this remains unclear.