The influence of the lipid composition of microalgal diets and cornstarch on the lipid classes and fatty acids of Ruditapes decussatus spat was studied. These aspects of the nutritional value of the diets are discussed in relation to the growth of the spat. Cornstarch is rich in carbohydrate, but is deficient in protein and lipids. The microalgal cells contains lipid as well as protein and carbohydrate. Tahitian Isochrysis cells contain phospholipids and triacylglycerols as majority lipids, whereas in the cornstarch particles the more abundant lipids are free fatty acids and phospholipids.The n-3 fatty acids were the most abundant acids in the microalgae whereas the n-6 fatty acids were in the cornstarch. The n-3 PUFA were not detected in cornstarch. Diets with a lipid composition high in phospholipids and triacylglycerols and in essential fatty acids produce good growth rates in spat of R. decussatus. However these elements alone are not sufficient to explain the quality of the diet for R. decussatus. In fact, the lipid content of the diet affects growth, but does not explain it totally and it is the carbohydrates content that explains the differences in growth found when we use diets with the same composition in lipids.

This work was funded by CICYT-CSIC.IEO projet I D number AGF95-1003-CO2.

10 páginas, 6 tablas

Peer reviewed