Effect of vitamin A compounds on bone deformity in larval Japanese flounder ( Paralichthys olivaceus)

This study was conducted to determine the effect of various vitamin A (VA) compounds, given through Artemia nauplii, on larval Japanese flounder. Artemia were enriched in a 10-l medium containing either 100,000 IU of retinol, retinyl palmitate, retinyl acetate or 100,000 μg of all- trans-retinoic acid; and fed to larvae during vertebral morphogenesis. The results of this experiment showed that during a short period of enrichment, less than 22 h, Artemia can absorb and metabolize the various VA compounds given with the emulsified oil. Retinoic acid was the predominant VA metabolite in Artemia enriched with either retinol, retinol palmitate or retinoic acid itself; the retinoic acid contents were 82, 50 and 99% of the total VA compounds, respectively. On the other hand, Artemia enriched with retinyl acetate contained a high amount of retinyl acetate; 72% of the total VA compounds. For this enrichment group, retinoic acid formed 20% of total VA compounds. Although the retinyl acetate enriched group contained the highest amount of total VA compounds, the growth of fish fed these Artemia was better when compared to other treatments. It was found that all the fish fed Artemia enriched with various VA compounds had compressed vertebrae. However, the survival of fish remained unaffected and high. Thus, the high concentrations of different VA compounds added in Artemia medium were toxic to flounder, probably due to the high content of retinoic acid, a VA metabolite formed in Artemia.