TRANSPORT OF ALPHA-TOCOPHEROL IN ATLANTIC SALMON (SALMO-SALAR) DURING VITELLOGENESIS

The transport of alpha-tocopherol was studied during vitellogenesis in Atlantic salmon that were fed diets with two levels of alpha-tocopherol. Alpha-tocopherol levels were measured in the flesh, liver, ovary and serum, and in the serum the alpha-tocopherol levels in the very low density lipoprotein (VLDL), low density lipoprotein (LDL), high density lipoprotein (HDL) and very high density lipoprotein (VLDL or vitellogenin) were also measured. Atlantic salmon store alpha-tocopherol mainly in their flesh because the muscle mass comprises 50% or more of live weight. During vitellogenesis the alpha-tocopherol content declined to about 10% of the level prior to maturation. The relative range of level of alpha-tocopherol in the lipoproteins was: HDL > LDL > VLDL > VHDL, irrespective of dietary levels of alpha-tocopherol. From the recent knowledge on lipid transport during vitellogenesis and the present data, we hypothesize that alpha-tocopherol is transported from peripheral tissues to liver by HDL, and further transported from liver to ovary by LDL. Vitellogenin appears to play a minor role in the transportation of vitamin E to the ovary.