PLASMA VITELLOGENIN LEVELS DURING THE ANNUAL REPRODUCTIVE-CYCLE OF THE FEMALE RAINBOW-TROUT (ONCORHYNCHUS-MYKISS) - ESTABLISHMENT AND VALIDATION OF AN ELISA

Rainbow trout, Oncorhynchus mykiss, vitellogenin (Vtg) was purified fr om plasma of E-2-treated male by direct anion exchange chromatography and some of its biochemical characteristics were studied. Our results demonstrated that, under SDS-PAGE conditions, rainbow trout Vtg was co mposed of two molecular forms of 390 and 176 kDa representing, respect ively, the dimeric form and the monomeric form of the molecule. The pu rified Vtg was used to raise a polyclonal antibody for Vtg (anti-Vtg). Using this anti-Vtg, a competitive enzyme-linked immunosorbent assay (EL-SA) was developed for the quantification of rainbow trout Vtg. The practical sensitivity range of this ELISA was 20-320 ng/ml (80-20% of binding) and the detection limit was 9 ng/ml. The intra- and the inte r-assay coefficients of variation(ar 50% of binding) were estimated at 1.8% (n = 10) and 3.9% (n = 13), respectively. This ELISA was validat ed by detecting changes in Vtg levels in rainbow trout at different ph ysiological stages, as well as in 2-year-old female rainbow trout thro ughout the reproductive cycle. (C) 1997 Elsevier Science Inc.