QUALITY OF TAMBAQUI (Colossoma macropomum) SEMEN CRYOPRESERVED IN DIFFERENT CONCENTRATIONS OF EGG YOLKAbstract
The aim of this study was to evaluate the effect of egg yolk (EY) addition on the sperm kinects after cryopreservation. We used twenty tambaqui males (n = 4 pools), which were induced homonally to spermiation with carp pituitary extract. Fourteen hours after induction, a seminal collection was performed. The semen from each pool was diluted with Ringer added 10% DMSO on the presence or absence of egg yolk (T1: no additional EY; T2: 5% EY; and T3: 10% EY). The treated semen was loaded in 0.5 mL straws, frozen in a nitrogen vapor vessel (dry shipper) (30 min / -153 °C), and then transferred to liquid nitrogen. Straws were thawed in a water bath at 37 °C / 30 seconds. The analyses of motility rate (%) and sperm curvilinear velocity (µm/s) were performed on computerized system (CASA). Data were expressed as mean ± standard deviation, and Tukey test was applied (P<0.05). There was a significant reduction in the percentage of motile spermatozoa and curvilinear velocity after the addition of egg yolk to the crioprotection solution, regardless of the concentration. Therefore, the addition of EY to Ringer + DMSO had negative effect on motility of tambaqui frozen sperm.
Keywords: extracellular cryoprotectant; freezing; reproduction