Yolk proteins in salmon (Salmo salar) oocytes, eyed eggs, and alevins differing in viability

Abstract

The developmental stages of oocytes, eyed eggs, and alevins from salmon (Salmo salar) were compared for their yolk protein composition. In oocytes, SDS–polyacrylamide gel electrophoresis showed high amounts of a protein with the molecular weight (Mr) of 94 000. In eyed eggs, the 94 000 protein decreased and was undetectable in the alevins. Furthermore, in eyed eggs the proteins of 67 000, 30 000, and 27 000 increased, while in the alevins the concentration of the 67 000 protein decreased and that of the 39 000 increased. Vitellogenin-specific antigen sites analyzed by immunoblotting were most pronounced with the proteins of 94 000, 67 000, 39 000, 30 000, 23 000, and 19 000. Separation of the yolk proteins by HPLC gave four peaks at 280 nm for all three developmental stages. Each peak consisted of several proteins as analyzed by SDS–polyacrylamide gel electrophoresis. The 7-day-old alevins sampled from groups of different parental origin showed differences in the amount of the 67 000 and 23 000 proteins. Expectancy of survival within the group in connection with a slow disappearance of the 67 000 and 23 000 proteins was statistically significant. A fast disappearance may be used as an indication of, but not as the reason for, a high mortality within one group of alevins.