ANALYSIS OF THE PRODUCTION OF ALL HOMOZYGOUS LINES OF RAINBOW-TROUT BY GYNOGENESIS

Homozygous gynogenetic (GE) rainbow trout (Oncorhynchus mykiss) were produced, using diploid gynogenesis with UV rays as an agent of sperm inactivation and heat shock as treatment for inhibition of first cleavage and restoration of diploid status. Their survival and growth performances were analysed in progenies from individual females, and compared with both diploid outbred control (D) and gynogenetics resulting from inhibition of meiosis II (GP). The homozygous status of GE fry was proved by electrophoretic control. Mean survival of GE groups was quite low (around 19% of D control at feeding start, vs. 63% in GP) but much depended on the founder female. A positive correlation was found between early survival of haploids and late survival of diploid GE fry from the same mother. Growth was also very reduced in both gynogenetics, though to a lesser extent (90 and 80% of D control at day 103 in GP and GE groups respectively).