| Cryopreservation of boar semen can increase the speed of genetic selection ,control the spread of infectious diseases,and increase the utilization value of the stud stock,besides it is conducive to the good strains'international exchange.This technique can't be used in production though after many years of hard work,the main reason is boar sperm's freeze tolerance is feebleness, compared to the others domestic animals.According to report,use the frozen sperm carries on breeding, sow's bearing young rate is lower than the natural mating .therefore this technology is hard to spread,and still in testing and researching phase right now.The cold resistance of boar sperm can be increased by added cryoprotectant into the extenders, it also can increase sperm livability, acrosome integrity and membrane integrity after freezing and thawing .In present study, Low Density Lipolipid (LDL), Soy lecithin and Trehalose were added in extenders to investegate the effects of them on boar sperm parameters after freezing and thawing, and the results were shown following:1.Low Density Lipolipid (LDL) can protect sperm from freezing damage during the sperm frozen-thawed process. In order to distinguish the efficiency of LDL extracted from different avian species, to confirm which one and how much of it has the best anti-freezing effect, LDL extracted from hen egg, duck egg, quail egg, pigeon egg and ostrich egg with the mass fraction of 0.06, 0.07, 0.08, 0.09 and 0.1 was added into the cryopreservation diluents of boar sperm separately (g/mL). The result showed that, after the frozen- thawed process, LDL extracted from hen egg, duck egg, quail egg and pigeon egg with concentration of 0.09 and ostrich LDL with concentration of 0.08 could protect sperm with highest livability of 40.33%, 35.63%, 31.47%, 43.33% and 36.40%, respectively. They were significantly better than that of other concentrations (P<0.05). Among the cryopreservation diluents and cryopreservation sperm prepared with the five avian species with the optimum concentration, it was found that the 0.09 pigeon LDL group showed 43.20% sperm livability, 52.57% acrosome integrity and 48.13% membrane integrity after thawing, all of them were better than that of other groups (P<0.05). Based on the most significant increase of the cold resistance ability that conferred by pigeon egg yolk LDL, it has a good performance on sperm cryopreservation. 2.More and more research focus on find effective impermeable cryoprotectant in recent years,Soy lecithin and Trehalose shown best performance in those research.In present study,Low Density Lipolipid (LDL) ,Soy lecithin and Trehalose were added and mixed in extenders to investegate the effects of them on boar sperm parameters after freezing and thawing.The result showed that, after the frozen- thawed process,three cryoprotectant mixed groups could protect sperm with higher livability ,they were significantly better than that of other concentrations (P<0.05). The sperm livability of the group which added LDL 0.07 g/mL,Trehalose0.05g/mL and Soy lecithin 0.05g/mL was 47.87% and it was the highest group,but there is no significantly difference between this group and the other two groups which add three kinds of cryoprotectant(P<0.01), besides with the increase of the solution concentration, the percentage of capacitated sperm was enhanced, the percentage of capacitated sperm of the group which added LDL 0.07 g/mL,Trehalose0.05g/mL and Soy lecithin 0.05g/mL was 47.87% and it was the highest group, significantly higher than the other groups(P<0.05).It demonstrated that three kinds of cryoprotectant mixed could be used for boar cryopreservation sperm.3.Low Density Lipolipid (LDL) ,Soy lecithin and Trehalose can protected the sprem and reduced the cryolesion on the SOD,CAT and GSH-Px in the balance and freezing procedure.The SOD activity of the group which added LDL 0.09 g/mL,Trehalose0.04g/mL and Soy lecithin 0.05g/mL was 106.23 and it was the highest group,significantly higher than the other groups(P<0.05).There is no significantly differnce of the CAT activity and the GSH-Px activity between the three kinds of cryoprotectant mixed groups.Based on the most significant increase of the cold resistance ability that conferred by the group which have LDL 0.09 g/mL, Trehalose 0.04g/mL and Soy lecithin 0.05g/mL, it has a good performance on sperm cryopreservation. |
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