Fatty acid composition of female and male clams (Ruditapes philippinarum): energy intake and temperature reliance

We analysed the effect of temperature, coupled with food ingestion rate (IR), on the fatty acid (FA) profile of female and male clams conditioned in two groups: L (low IR at 14 and 18 degrees C) and H (high IR at 18 and 22 degrees C). Significant differences for group L, both 18L and 14L with low IR and slow gonadal development, owed to differences in energy balance between 18L clams (negative energy balance) and 14L clams (positive energy balance). Plasmalogens (DMA 18: 0) and non-methylene-interrupted FAs might protect against reactive oxygen species and preserve the integrity of the cell membranes during food stress in 18L clams. Differences in composition for group H, both 18H and 22H with high food intake, positive energetic balance and complete and similar gonadal occupation index (GOI), probably owed to the greater energy levels at 18 degrees C than at 22 degrees C. Clams at 22 degrees C H increased the oxidation of short-chained PUFA 18:3 omega 3 and 18:3 omega 6 to maintain the same GOI as 18H clams. Regarding the sexual differences, the greater accumulation of 20:5 omega 3 and 20:4 omega 6 in females might be related with oocyte maturation and release during spawning, while the greatest levels of 22:6 omega 3 in males might be involved in spermatocyte membranes synthesis.