Quantitative Characteristics of Rainbow Trout, Oncorhynchus Mykiss, Neo-Males (XX Genotype) and Super-Males (YY Genotype) Sperm

Rainbow trout homogametic males, (XX or YY sex genotype), can be obtained, respectively, through masculinisation of genetic females or induced androgenesis. Aim of this study was to compare reproductive potential of neo-males (XX) and super-males (YY) with heterogametic males (XY). We measured spermatozoa motility parameters, sperm concentration, osmolality and characterized protein profiles in samples of stripped and testicular sperm obtained from XY and YY males, and testicular sperm of XX males. The motile spermatozoa, as measured by both subjective method and CASA, showed no differences between testicular sperm of XX males and stripped sperm of XY and YY males whereas testicular sperm of XY and YY males had significantly lower sperm motility. Result of protein densitometry showed similarities in protein profile between seminal plasma of XY and YY males and testicular fluids of XX males. Testis of XX males showed specific histological structures of cysts consists hypertrophied Sertoli cells. Keywords—fish, genotype, rainbow trout, sperm.