Variations of lipid and fatty acid contents during the reproductive cycle of the anthozoan Renilla koellikeri.

Abstract

Lipid and fatty acid contents were monitored in the sea pansy Renilla koellikeri during its reproductive cycle. The fluctuations of lipids and fatty acids were closely related to sexual development and gonads represented the principal site of lipid storage in the colony. Between April and May, fatty acids and lipids greatly accumulated just prior to spawning. The subsequent decrease of lipid and fatty acid contents in June probably resulted from loss due to spawning. Fatty acid composition was assessed for the whole animal and was compared between male and female gonads, and between gonads and somatic tissues. Arachidonic acid (AA) was the principal fatty acid in the whole colony followed by palmitic acid and eicosapentaenoic acid (EPA). The examination of fatty acid variations in gonads showed that EPA and AA were highly incorporated in eggs during the month preceding spawning, whereas in the same period, EPA was the only fatty acid to accumulate in spermatophores. The differences of fatty acid levels observed in gonads reflected sex differences observed in colonies. The seasonal variations of the omega6/omega3 ratio of the colonies were largely influenced by EPA and AA, and appeared as a reliable indicator of the sexual maturity of the sea pansy.