The experiment was conducted in order to evaluate the effect of 3 diluents BTS+KCl - D1, BTS+2KCL - D2 and BTS+Sodium Citrate - D3) and three different times (hour 0, 72 hours and 144 hours) in Piracanjuba (Brycon orbignyanus) semen at 4°C. The assay aimed to test usefulness of BTS (Betsville Thawing Solution) diluent medium, added to Sodium citrate and Potassium clorate, in maintenance of spermatic immobility and of its conditions to conserve semen characteristics as spermatic motility rate and duration. Satisfactory results were found until at 144 hours of cooling for this specie. The mean spermatic motility in the in natura state was 94 ± 5.48% with mean duration of 55.6 ± 32.25 seconds (s). For diluted semen, motility and duration means were 76.00 ± 1.86% and 56.6 ± 6.54 s, 77.00 ± 1.86% and 54.6 ± 6.54 s, and 74.33 ± 1.86% and 75.0 ± 6.54 s, respectivaly, for diluents D1, D2 and D3, in this order. Significant differences were not observed among diluents and they showed similar effects in at different times. At 0 and 72 h of analysis showed higher spermatic motilities than that ones at 144 h, but durations of spermatic motility did not show differences in these times. The semen mean spermatic concentration was 8.21 ± 2.26 X 10(9) sptz/mL. Some samples showed spermatic motility before semen activation (fore-activation) principally after 96 hours of cooling. Thus, BTS medium diluent may be recommended for fish semen conservation, since its osmolarity is elevated.
Brycon orbignyanus; BTS; cooling; piracanjuba; semen
