Biochemical composition of eggs from repeat and first-time spawning captive Atlantic halibut ( Hippoglossus hippoglossus)

Abstract

Eggs from a repeat and two first-time spawning Atlantic halibut were compared for biochemical content which was then related to fertilization success and larval survival. Levels of total lipid, neutral and phospholipid subclasses were determined in batches over the spawning season. Fatty acid and amino acid measurements were also carried out on selected samples. Eggs from the repeat spawner averaged 81% fertilization compared with 56% for the first-time spawners' eggs. The dry weight of eggs for all fish decreased in subsequent batches and was significantly lower in the first-time spawners' eggs ( P < 0.001). Eggs from the first-time spawners were significantly lower in total lipid ( P < 0.05), triacylglycerol ( P < 0.01) and sterol ( P < 0.005) content. These eggs also had less of two essential fatty acids; both docosahexaenoic acid (DHA) and arachidonic acid (AA) were significantly lower ( P < 0.05 and P < 0.0005, respectively). The phospholipid subclass and free amino acid content were comparable to published data for Atlantic halibut eggs. The results of the study indicate that repeat spawning Atlantic halibut produce biochemically different eggs from first-time spawners which may relate to the better ‘quality’ of those eggs in terms of fertilization success and larval survival.