Variations in Fatty Acid Profiles and Their Relation to Size and Spinal Deformities in Pike Perch (Sander lucioperca) Larval to Juvenile Stages

Abstract

Even though pike perch aquaculture has grown during the last decade, early development still forms a bottleneck for the industry. High mortality rates, cannibalism, and deformations continue to limit hatchery output and, by this, the economic efficiency for aquaculture endeavors with this species. Hereby, fatty acids (FAs), particularly polyunsaturated FAs (PUFAs), play a crucial role in larval development by influencing growth and a broad range of developmental processes. This study investigated FA pattern changes throughout key developmental stages from larval to juvenile pike perch. Hereby, a particular focus was placed on associations with growth and spinal deformation, as these are two major challenges in pike perch rearing. Comparing industry reared larval stages during grading, alongside maternal and dietary FA sources, shifts in FA composition were assessed. A consistent decline in long-chain PUFA (LC-PUFA) levels was observed. Shifts in the FA-profiles identified in larvae at 42–43 days post hatch (dph) marked a critical developmental window during metamorphosis. Although feed analyses confirmed a sufficient provisioning of FAs, findings suggests that higher LC-PUFAs intake may be required during this period. Phenotypic comparisons showed that FA-patterns of larger specimens are more closely resembling those of specimens with progressed developmental status. Deformation status, however, showed no significant connection to FA pattern variations, except for a tendency towards decreased saturated FA (SFA) levels during metamorphic stages, potentially reflecting elevated energy demands of deformed specimens. The consistently undetectable levels of mead acid (C20:3n−9) indicated a sufficient supply of essential FAs throughout the rearing period. The variable accumulation of LC-PUFAs suggests differences in metabolic capacities linked to developmental stages. This highlights the potential for larval and juvenile stage-specific nutritional strategies in pike perch hatchery production.