THE EFFECT OF INDIVIDUAL MALE POTENCY ON FERTILIZATION ABILITY OF FRESH AND CRYOPRESERVED MILT OF RAINBOW-TROUT, ONCORHYNCHUS-MYKISS (WALBAUM)

The goal of the present study was to examine individual male potency i n rainbow trout, Oncorhynchus mykiss (Walbaum), expressed as the ferti lization ability of fresh and cryopreserved sperm. One female and four males bearing genetic markers enabling determination of the progeny p aternity were chosen as gamete donors. Samples of eggs were inseminate d with sperm from separate individuals or with pooled sperm. Genetic e xamination of the progeny obtained after fertilization of eggs with po oled milt showed differences in male potency. The proportions of offsp ring sired by four individual males after fertilization of eggs with t he fresh milt were similar to those obtained after fertilization with cryopreserved milt (correlation r = 0.95; n = 4: P < 0.05). These prop ortions did not correlate with the proportions of progeny resulting fr om fertilization of eggs when sperm was not pooled.