Incorporation of yolk fatty acids into body lipids of goldfish (Carassius auratus L.) larvae raised at two different temperatures.

In five separate experiments, eggs from a single female goldfish were fertilized at 20°C. They were incubated at 22°C for 6 hours, after which some of the eggs were transferred to 13°C. When a defined post-hatch developmental stage was reached, lipid extracts were prepared from larvae, both with yolk sacs intact and after removal of the yolk sac by dissection. Other larvae were sampled at yolk exhaustion. Gas chromatographic analysis of fatty acid profiles revealed that larvae incorporated 16:0, 18:0, 20:4 (n-6) and 22:6 (n-3) into their tissues in proportions higher than those present in the eggs from which they were derived. At 22°C, these trends were particularly apparent at yolk exhaustion. At 13°C, proportions of polyunsaturated fatty acids in the bodies of newly hatched larvae were higher than those in the 22°C larval bodies. Monounsaturated fatty acids were preferentially depleted during development, especially in larvae from high quality eggs. No dependence of egg quality, as assessed by larval viability at 22°C, on total egg lipid mass or fatty acid composition was found. Larvae from the lowest quality eggs showed a reduced preference for incorporation of (n-3) polyunsaturated fatty acids into their tissues.