Cryopreservation of Chinese sturgeon (Acipenser sinensis) sperm

This investigation studied the effectiveness of techniques to collect sperm from Chinese sturgeon males and developed examination methods fon the viability of sperm. Further, a series of experiments tested a variety of sperm diluents while also selecting suitable cryoprotectants and its concentration, determined optimal equilibrium time, cooling rate and freezing point. Additionally, the effects of the cryo-preservation methods on the viability of sperm were tested while also determining the fertilization success with sperm cryo-preserved with three different diluents. The results indicated that the diluent D-5 (8.85g/L NaCl; 0.20g/L and 0.40g/L NaHCO3) was the best sperm diluent, and 12% DMSO was a suitable cryo-protectant keeping 0.5-2h as the equilibrium time at 4. Combining D-5 with DMSO under the described conditions seems to be the most suitable method for sturgeon sperm cyro-proservation while employing the cooling rate at 2/min and freezing point at -6 keeping the sperm for 10 min before placing into liquid nitrogen. Fertilization tests, D-3, D-5 and D-6, (whose effects were similar in the diluents tests), were used to compare the effects of cryopreserved sperm on fertilization success. The results indicated that the effect of D-5 in thawed sperm fertilization was the best among all three diluents having the least negative effect. The resulting in a fertilization rate was 83.8% and survival rate of larvae reached up to 68.1%. However, comparing with the control, the survival rate of D-5 was still noticeably smaller. The reason needs to further study.