Abstract：A large scale of cold water fish germplasm resources extensively distribute in Irtysh River of China, the burbot, Lota lota (Gadidae, Telestei) is as one of cold water groundfish, and the establishment of sperm cryopreservation technology and cryobank is of great significance to its germplasm resources preservation. In the present study, 7 kinds of sperm diluents were prepared with the basic liquid including inorganic salt, glucose, sucrose and fetal bovine serum(FBS). The sperm were diluted at a ratio of 5∶1 (extender: sperm), the motility were observed and recorded under the microscope. The results indicated that the sperm expressed certain motility in the SS, D15, and CM ((13.33±2.89)%~(8.33±2.88)%). On this basis, 22 kinds of gradient dilutions (SS-00~SS-10 and D15-0~D15-7) were prepared, and then diluted sperm, observed motility as in the same way. The results indicated that the motility were relatively higher in the SS-0(56.67±5.77)%, SS-2(63.33±5.77)%, SS-5(53.33±5.77)% and D15-7 (63.33±5.77)%, closed to the fresh sperm motility (76.67±5.77)% (P＜0.05). Mixed cryoprotectants and DM were prepared with dimethyl sulfoxide (DMSO) and MeOH at a ratio of 3∶2. And sperm were diluted by diluents selected, SS-5 and D15-7 at a ratio of 5∶1 (extender: sperm), then added 5%~12%DM, respectively, for sperm cryopreservation. Before cryopreservation, the sperm was activated with 2 ℃ freshwater, observed and recorded the motility under microscope. The results indicated that the motility of 5% DM within the SS-5 and D15-7 was (73.33±5.77)%, there were no significant difference with fresh sperm (P＞0.05), but the sperm motility almost was 0 with the rised DM concentration to of 10%~12%. After cryopreservation, the frozen sperm motility results showed that with the DM concentration of up to 6% in the SS-5, the sperm motility were relatively higher of (26.67±5.77)% (P＜0.05). In addition, when the DM concentration was 7% in the D15-7, the motility was also relatively higher (26.67±5.77)% (P＜0.05). The present study results provide the theoretical and technical basis for cryopreservation of spermatozoa of the burbot from Irtysh River of China.
