The Effects Of Epimedium Polysaccharide On Goat Semen Cryopreservation

Artificial insemination(AI)were applied to goat breeding and reproduction in the 1980 s.Recently,with the development of animal husbandry,the traditional goat farming industry has also begun to scale and intensive development.The AI has developed rapidly and is increasingly used in farm production.Semencryopreservation is one of the key factors in AI.In order to achieve long-term preservation of semen,the semen is stored in liquid nitrogen at-196 °C to reduce or completely stop sperm metabolism.Semen cryopreservation technology can improve the utilization value of rams,accelerate the improvement of varieties,reduce the breeding of rams,and is not limited by time and region.However,sperm produces excessive amounts of reactive oxygen species(ROS),which will reduce sperm quality and pregnancy rates for sperm oxidative damage during cryopreservation of goat semen? Polysaccharide,also known as polysaccharide,consists of more than 10 monosaccharides.It is a natural polymer compound with strong polarity and complex structure formed by polymerization of glycosidic bonds.It has various pharmacological activities,such as antioxidant activity,immunomodulatory activity and Antitumor activity,widely used in medical,functional foods and pharmaceuticals.In this study,a natural Chinese herbal antioxidant extract,Epimedium polysaccharide(EPS),was added to the frozen dilution of goat semen.Sperm motility,plasma membrane integrity rate,acrosome integrity rate,total antioxidant capacity(T-AOC),malondialdehyde(MDA)and reactive oxygen species(ROS)content,semen ATP levels,superoxide dismutase(SOD),catalase(CAT),sperm mitochondrial membrane potential and changes in sperm ultrastructure before and after freezing were tested to investigate the effect of Epimedium polysaccharides in the process of cryopreservation of goat semen.The main results of this research were as following:1.Different concentrations(1.0,2.0,3.0,4.0,5.0 mg/mL)EPS were added to the goat semen dilution.The results showed that the sperm motility(52.10%),plasma membrane integrity(57.01%),tail plasma membrane integrity(52.37%)and acrosome integrity rate(52.45%)in 3.0 mg/mL EPS group were significantly higher than those of the control group(P<0.05).Sperm motility,plasma membrane integrity rate and acrosome integrity rate were lower than 3.0 mg/mL epimedium polysaccharide group at 2.0 mg/mL,but still significantly higher than the control group(P<0.05).There was no significant difference between the 5.0 mg/mL Epimedium polysaccharide group and the control group(P>0.05).2.Antioxidant capacity was assessed by activity of T-AOC,SOD,CAT,ROS,MDA.The results showed that T-AOC(8.97 U/mL),SOD(253 U/mL)and CAT(14.77 U/mL)in 3.0 mg/mL EPS group were significantly higher than the control group(P<0.05).The levels of ROS(2535.11 nmol/mL)and MDA(0.44 nmol/mL)in 3.0 mg/mL EPS group were significantly lower than those of the control group(P< 0.05).The activity of T-AOC and SOD in 2.0 and 4.0 mg/mL EPS groups were significantly higher than those of the control group(P<0.05),and the content of MDA was significant lower than the control group(P<0.05),but the ROS level and catalase(CAT)activity were not significantly different from the control group(P>0.05).3.Sperm energy metabolism was assessed by ATP levels and mitochondrial membrane potential in frozen-thawed sperm.The results showed that ATP level and mitochondrial membrane potential were significantly higher in the treatment group than in the control group.The ATP level(0.60 ?mol/mL)and mitochondrial membrane potential in 3.0 mg / mL EP were the highest in all groups(P>0.05).4.Goat semen causes varying degrees of damage to the sperm structure through cryopreservation.Ultrastructural observation of sperm showed that the structure of fresh sperm spermatozoa was complete,the boundary was clear,and the edges were neat.After freezing,the goat sperm plasma membrane and the apical body and outer membrane mostly expand,break or disappear,the nuclear contents are lost,and the tail plasma membrane is swollen,damaged,shedding or tail distortion.In summary,this study incidate that the addition of EPS to the frozen dilution improves sperm quality by reducing oxidative damage during goat sperm freezing,meanwhile,3.0 mg/mL EPS is considered to be the optimal concentration.It provides a reference for the application of cryopreservation and artificial insemination of goat semen.