Cryopreservation Technology On Duck Semen

In order to develop cryopreservation techniques for duck semen and to be applied to the conservation of ducks genetic resources, breeding, and commercial production, experiments were carried out to determine optimum diluents,cryoprotectants,equilibration times,thawing temperature for frozen drake semen and to evaluate the individual difference of freezability of semen. The results were as follow:1. Effect of diluents on frozen semenSeven diluents were studied to determine appropriate diluent. The diluent that included potassium citrate, sodium glutamate, glucose and inositol etc, gave the highest post-thawing motility,the average motility was 0.59.The recovery percent of motility of the diluent was 70.83%,significantly higher than other 6 diluents(P＜0.01). The diluent was determined as an optimum diluent for freezing.2. Determination on optimum cryoprotectants,equilibration time, thawing temperature.Effects of four concentrations of cryoprotectants including glycerol,DMSO,DMA,DMF were studied. The results showed: in 10% DMSO, post-thawing motility was highest,the second was 8% glycerol.The motility after freezing and recovery percent of motility of 10% DMSO and 8% glycerol were 0.58, 0.54 and 73.12%,68.12%.The difference between 10% DMSO and 8% glycerol was not significant(P＞0.05).10% DMSO was selected as cryoprotectant for cryopreservation. Comparing the effects of various equilibration times and thawing temperature of 10% DMSO,equilibration times 15 min and thawing temperature 40℃ gave the highest post-thawing motility.3. Individual difference in freezability of drake semenThe difference in semen freezability of 10 drakes were determined. The results indicated that there were significant difference in post-thawing motility and fertility rate of 10 drakes semen(P＜0.01). The post-thawing motility and recovery percent of motility of No.5 drake spermatozoa was highest,0.70 and 87.19%.The post-thawing motility of No.7 and No.10 drakes were 0.63 and 0.61. Motility of No.5,7,10 drakes semen were significantly higher than other 7 drakes(P＜0.01). Fertility rate for days 2 to 5 of No.5 drake was 64.75%,higher than other drakes(P＜0.01).Fertility of No.2 drake was 0. The results showed that there was significant individual difference in freezability of drake semen.