| Semen cryopreservation is a kind of important technique of preserving the germplasm resources with the sperm cell preservation technology which has been developed together with the application and development of artificial insemination technology.At present,it is an in the fields of agriculture,biology and medicine.Cryopreservation semen preservation technology has been widely used in the production of the livestock industry.Semen cryopreservation can significantly improve the utilization of male and female,reduce the number of their breeding,and reduce the spread of related infectious diseases.Lentinan polysaccharide as a functional polysaccharide with immunoregulation and antioxidant function has been studied extensively in many fields.A large number of studies had shown that supplementation of antioxidants in semen cryopreservation extenders could improve the quality of semen after freezing and thawing.However,lentinan polysaccharide has not been reported in semen preservation.Therefore,this study explored the effects of different concentrations of lentinan polysaccharide on dairy bull frozen semen with the movement performance,structure and antioxidant properties of frozen-thawed sperm.In order to reveal the effects of lentinan polysaccharide on the cryopreservation of frozen semen of dairy bull and to screen out the optimal concentration.The main results obtained in this study are as follows:1.Adding a certain concentration of lentinan polysaccharide in dairy bull semen cryopreservation extenders can increase the sperm motility,progressive rate,straight-line velocity,curvilinear velocity,average path velocity,and the linearity of dairy bull sperm.Compared with other treatment groups,the 25 mg/L lentinan group had the best preservation effect,significantly improving sperm motility(44.86%),progressive rate(35.21%),linear rate(84.87 ?m/s),curve velocity(122.75 ?m/s),average path rate(104.74 ?m/s)and linearity(79.44%)(P< 0.05).The results showed that the addition of 25 mg/L lentinan polysaccharide group had best protection for frozen sperm.However,the movement characteristic of sperm of the with 50 mg/L and 100 mg/L lentinan polysaccharide groups was significantly lower than that of the control group(P< 0.05).2.Adding a certain concentration of lentinan polysaccharide in the dairy bull cryopreservation extenders can effectively increase plasma membrane integrity and acrosome integrity rate of sperm after freezing and thawing.Adding 5 mg/L and 25 mg/L lentinan polysaccharide was the best,plasma membrane integrity and acrosome integrity rate of sperm after freezing and thawing were 46.84% and 48.10%,62.83% and 64.21%,respectively.They were significantly higher than control groups(P< 0.05).However,the differences between 5 mg/L and 25 mg/L groups was not significant.In the group with 1 mg/L lentinan polysaccharide,there was no significant difference in the plasma membrane integrity and acrosome integrity of sperm after freezing and thawing compared with the control group.While in the lentinan polysaccharide group with 50 mg/L and 100 mg/L,the plasma membrane integrityand acrosome integrity of sperm after freezing and thawing were significantly lower than that of the control group(P< 0.05).Sperm motility was strongly correlated with acrosomal integrity and plasma membrane integrity(r=0.977;r=0.979),showing a significant correlation(P< 0.05).There was a strong correlation between acrosomal integrity and plasma membrane integrity(r=0.990),showing a significant correlation(P< 0.05).3.The addition of 5 mg/L and 25 mg/L lentinan polysaccharide in the dairy bull cryopreservation extenders can effectively increase the activity of T-AOC and GSH-Px in frozen-thawed dairy bull sperm and reduce the content of MDA.Compared with other groups,the activity of T-AOC and GSH-Px in the 25 mg/L treatment group was significantly higher than that in other groups(P< 0.05).MDA concentration in the 25 mg/L treatment group was significantly lower than that of the control group(P< 0.05),but there was no significant differences with that of the 5 mg/L group.T-AOC of dairy bull sperm in the extender group with 50 mg/L and 100 mg/L lentinan polysaccharide was significantly higher than that in the control group(P< 0.05),but the both were significantly lower than that in the 5 mg/L group(P< 0.05),while GSH-Px activity was not significantly different from that in the control group.When 50 mg/L and 100 mg/L lentinan polysaccharide were added into the cryopreservation extenders,the MDA content of frozen-thawed sperm was significantly higher than that in other groups(P <0.05),but there was no significant difference between the two groups.The activity of T-AOC and GSH-Px in the lentinan polysaccharide group with 1 mg/L was higher than that in the control group(P< 0.05).And the concentration of MDA was lower than that in the control group,but the difference was not significant(P> 0.05).Sperm motility was negatively correlated with MDA concentration(P< 0.05),while sperm motility was positively correlated with the activity of T-AOC and GSH-Px(P< 0.05).MDA concentration was negatively correlated with the activity of T-AOC and GSH-Px,but the correlation was not significant.The activity of GSH-Px was significantly correlated with the activity of T-AOC(P< 0.05).Lentinan polysaccharide in dairy bull semen cryopreservation extenders as protectant could effectively improve the quality of sperm.The indexs of sperm motility,progressive rate,straight-line velocity,curvilinear velocity,average path velocity,and the linearity significantly increased after freezing and thawing.Plasma membrane integrity and acrosome integrity after freezing and thawing of dairy bull sperm also increased by adding lentinan polysaccharide in cryopreservation extenders.Meanwhile the activity of T-AOC and GSH-Px were increased,and MDA content was reduced.Therefore adding appropriate concentration of lentinan polysaccharide in dairy bull semen cryopreservation extenders has a certain protective effect on sperm,which was of great significance for the study of cryopreservation preservation of dairy bull semen. |
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