Effect of Milt Volume Equalization in Mixed Milt Fertilization of Caspian Brown Trout Salmo Trutta Caspius on Genetic Contribution of Breeders to F1 Progeny

Due to importance of genetic contribution of all broodstocks in artificial propagation of Caspian brown trout Salmo trutta caspius for increasing gene pool in future progeny, effects of milt volume equalization of broodstocks in mixed milt fertilization were assessed. (Ne) was calculated through equal gamete mating of four male and female breeders in two trearments. Assesment of genetic contribution were carried out by polymerase chain reaction using three polymorphic uniqued allel microsattelite loci (Str 591, 73, 58). Parental and progeny genotype were determined by automated ABI PRISM sequencer system and allels were scores by using Gene Mapper software. Pedigree tracing was performed in the basis of exclusion method in FAP program using three polymorphic microsatellite loci in breeders. Ne was calculated as 0.84 and 0.51 in the first and second treatment, respectively which subsequently reduced genetic diversity in alevins significantly (P>0.05). Equalization of milt volume and ova number not only did not result in balanced contribution of breeders, but also produced large variations in contribution to progeny, especially among males. Final results confirmed that real increasing of Ne in artificial breeding of Caspian trout breeders needs serious modifications in fertilization design of breeders in artificial breeding centers in Iran.