Vitamin A in salmon aquaculture

Cand. scient. Robin Ørnsrud will defend his Dr. scient. thesis "Retinoids in salmonid aquaculture with special emphasis on developmental deformities" on Friday September 12 at the University of Bergen.

The thesis investigates whether the varying and sometimes high concentrations of vitamin A in salmon feed inflicts any negative effects on salmon health.

The results show that fish with a chronic high vitamin A intake may suffer from reduced growth, abnormal vertebra formation and increased mortality. Although a chronic high vitamin A intake may cause negative effects in farmed salmon, it is completely safe for humans to consume such salmon. Furthermore, the interaction between high vitamin A status in salmon eggs in combination with high egg incubation temperature was investigated for possible effects on vertebral development. The results show that egg vitamin A status does not cause mal-development while high egg incubation temperature alters vitamin A homeostasis and causes mal-formation of internal organs and bone structure although spinal deformities were not found. The current thesis was partly conducted in collaboration with Marine Harvest and Nutreco Aquaculture Research Center.

Robin Ørnsrud (30), originally from Harstad in Troms county, submitted his Cand. scient thesis in nutrition at the Institute of Nutrition, Directorate of Fisheries (now National Institute of Nutrition and Seafood Research, NIFES) in 1998. After working for one year as a research assistant at the Institute, he commenced his Dr. scient thesis in 2000. Ørnsrud is now engaged as a researcher at NIFES where he will continue his work with vitamin A and bone development.