Assessment of ability of endangered Caspian brown trout, Salmo trutta caspius (Salmonidae) in production of semen with desirable quality

Abstract

To assay the effects of stripping frequency on semen characteristics of Caspian brown trout, Salmo trutta caspius, the chemical composition of seminal fluid, sperm production (semen volume, sperm density, spermatocrit,) and sperm motility characteristics (percentage and duration of motility) were investigated over four times stripping during the spawning season. According to data, semen volume, sperm density, osmolality and the concentrations of Na+, Cl−, K+, Ca2+, Mg2+ and total protein gradually decreased by increasing of stripping frequency. The values of glucose and triglyceride had no significant changes over four times stripping. Also, the values of semen pH, the percentage (5 s after activation) and duration of motility were statistically stable until third stripping but a decrease was recorded for these parameters in the fourth stripping. As well as, significant positive correlations were found for sperm density vs. K+, Cl−, Na+, Ca2+, Mg2+, total protein, spermatocrit; the percentage of motile spermatozoa vs. Ca2+, Mg2+, K+, Cl−, Na+, total protein, and also the duration of motility vs. K+, Cl−, total protein and pH. In text, specific objectives of this study have been expressed.