Changes of total carotenoid and lipid content in scallop tissues of Chlamys nobilis (Bivalve: Pectinidae) during gonad maturation

The noble scallop Chlamys nobilis is an important edible marine bivalve, which has been cultured in the Southern Sea of China since 1980s. Our previous study showed that the total carotenoid content (TCC) in this species was related to body tissue, shell color, and gender, which was the highest in the ovary of the scallops with orange shell and adductor muscle. In the present study, TCC and total lipid content (TLC) in three tissues of adductor muscle, mantle and gonad at different days were determined and compared using four groups of scallops including gonad mature male (MM), gonad mature female (MF), gonad gametocytogenesis male (GcM), and gonad gametocytogenesis female (GcF) and correlations between TCC and TLC for different tissues were analyzed in order to find out how they change during gonad maturation and whether they have correlation with each other in this species. All employed scallops were from the same family produced in autumn 2008 and had the same orange shell, mantle and adductor muscle with higher TCC. The present results showed that both TCC and TLC changed during maturation, but changing trend was different among tissues. In adductor muscle, TCC increased for MM and MF, but decreased for GcM and GcF; TLC had no significant change for all groups. In mantle, TCC significantly changed only in the GcF, which decreased from 327.18 μg g− 1 to 257.96 μg g− 1; TLC strikingly changed only in the MF, which increased from 5.33% to 6.77%. In gonad, TCC decreased in MM and increased in other groups; TLC increased in all groups. Particularly interesting and important, a significantly positive correlation (P < 0.05) between TCC and TLC was detected in the gonad tissues during maturation, which was also for the first time reported in marine mollusks. The present results also firstly demonstrated that both carotenoid and lipid not only were significantly accumulated in gonad, but also might be transferred from other tissues during maturation in mollusks, particularly in the female.

► Both total carotenoids and lipids content (TCC and TLC) were tissue-specific.
► They changed and were accumulated significantly in gonad during maturation.
► Both carotenoids and lipids were transferred from other tissues to gonad.
► A significantly positive correlation between TCC and TLC only existed in gonad.