| Semen cryopreservation is the most suitable way for long-term storage of poultry genetic resources and it can reduce the cost of breeds conservation. Currently, the fertilization rate of chicken frozen semen is about 60% and it is very unstable (0%-90%), so it is not widely used. Therefore, this paper used DMA as cryoprotectant and pellets to freeze black silkies chicken semen. Several factors were studied, such as the different kinds of semen diluents, balance times, concentrations of DMA, thawing equipments and breeds of chicken and the sperm vitality, fertilization rate and hatching rate were tested.The results showed that:? Screening of the semen diluents:the LR diluent was the best among the four kinds of diluents judged by the vitality, fertilization rate and hatching rate, and the motility was 0.64, fertilization rate was 49.49%, the hatching rate was 40.11%, and there was significant difference (p<0.05) with diluent F, B and L.? Screening of the two kinds of balance times:for the balance time of the first step, the 30 min group was the best and the motility was 0.64, fertilization rate was 50.73%, the hatching rate was 48.59%, and there was significant difference with any other balance time groups (p<0.05). For the balance time of the second step, the 10 min group was the best, and the motility was 0.63, fertilization rate and hatching rate were 52.14%,51.22% respectively.? Screening of the concentration of DMA:The most suitable concentration of DMA for black silkies chicken was 6%, and there was significant differences than any other concentrations (p<0.05), and the sperm motility was 0.64, fertilization rate was 46.67%, the hatching rate was 40.68%.? Screening of the thawing methods:there were 3 kinds of thawing methods, such as the thermostatic waterbath, thermostatic funnel, thermostatic plate. It could? get the best results when many frozen semen pellets was thawed together with the big thin-walled glass tube, until the sperm particles were melted to 1/3 in 60? thermostatic waterbath. The motility was 0.59, fertilization rate was 23.08%. There were significant differences for the sperm vitality among the group of 50? thermostatic plate,60? thermostatic waterbath and 40? thermostatic funnel (p< 0.05), and there were no significant differences among the four groups for the fertilization rate (p> 0.05).? The influence on the frozen semen effect of different chicken breeds:for roosters, the motilities of the black silkies fowl semen were better than that of white leghorn wether before or after freezing, and there were significant differences (p< 0.05). As for the hen, it could get very good fertilization rate (74.19%) and hatching rate (67.74%) when the thawed black silkies semen was inseminated into the same kind of hens and there was significant higher than that of White Leghorn, Esa brown breeds (p<0.05) and also higher than the average result rported in the literatures (60%).Therefore, the optical procedures was diluting black silkies rooster semen with LR diluent and balancing for 30 min, adding 6% DMA and balancing for lOmin, dropping directly in liquid nitrogen with 50?L, thawing frozen semen particles with 60? thermostatic waterbath. Then it could get a fertilization rate of 74.19% and hatching rate of 67.74%, which were similar to the international level when the inseminating volume was 0.2 mL and the interval was two days. In addition, it was also a good result that the thawed sperm motility was coincide with the fertilization rate, which would benefit to the future chicken semen research. |
PDF Full Text Request