A comparison of retinol, retinal and retinyl ester concentrations in larvae of Atlantic halibut (Hippoglossus hippoglossus L.) fed Artemia or zooplankton

Atlantic halibut (Hippoglossus hippoglossus L.) larvae were fed enriched Artemia or zooplankton in duplicate tanks from 0 to 60 days after first‐feeding. Both diets and the larvae were analysed for vitamin A (VA) in order to confirm earlier findings, in which Artemia fed larvae had lower levels of VA compared with larvae fed zooplankton. Furthermore, we wanted to investigate the composition of the retinoids in the larvae. The results showed that Artemia and zooplankton contains low levels of VA, probably too low to sustain the assumed requirement. Nevertheless, larvae fed Artemia had the same level of retinal and retinol as larvae fed zooplankton. We found a significant lower level of retinyl esters in larvae fed Artemia. The total VA level was lower in larvae fed Artemia only at the end of the feeding trial after the onset of metamorphosis. Our conclusion is that feeding Artemia to Atlantic halibut larvae is not likely to cause VA deficiency.