Effects Of Astaxanthin On The Quality Of Semen During Normal Temperature Preservation

In recent years,animal husbandry has developed rapidly and the pig industry tends to be scaled,intensive,and highly efficient.The technology of artificial insemination of pigs has been held in great honour in the farms and has been widely applied in production.The quality of boar semen will decrease significantly with the extension of the in vitro storage time.One of the main causes of these adverse reactions is the imbalance between the level of reactive oxygen species(ROS)and the antioxidant system.In fact,an appropriate concentration of ROS is beneficial to spermatozoa,which can cause spermatozoa to undergo acrosome reaction,hyperactivation,and capacitation.However,once ROS is overdose,it will directly damage organelles,membranes,and sperm DNA,leading to sperm apoptosis and death.Many studies have shown that the addition of antioxidants can effectively protect against sperm damage caused by oxidative stress.In this study,different concentrations of astaxanthin,a natural anti-oxidant,were added to the BTS from normal pig semen at room temperature to preserve the dilution,and sperm motility,plasma membrane integrity,acrosome integrity,and total antioxidant activity were measured at different time points.T-AOC,MDA,sperm motility parameters,ROS,semen ATP levels,sperm mitochondrial membrane potential,and major enzymes involved in antioxidant enzymes and energy metabolism in semen.Astaxanthin is used as a strong antioxidant in the preservation of pig semen at room temperature to provide a theoretical basis.This study mainly obtained the following results:1.Astaxanthin with different concentrations(0.10,0.20,0.25,0.30,0.40,0.60,0.80,and1.00?g/mL)was added to the BTS of normal pig semen at room temperature,which has a positive effect on the preservation of porcine sperm at room temperature.Among them,the storage effect of 0.25?g/mL astaxanthin was best in BTS,and the porcine sperm motility,head plasma membrane integrity,tail plasma membrane integrity,and acrosome integrity rate at the fifth day of storage at 17°C were:65.33%,73.45%,77.50%and 73.45%were significantly higher than those in the control group(P<0.05).However,sperm motility was significantly lower in the astaxanthin range of 0.60 to 1.00?g/mL than in the control group(P<0.05).2.Adding different concentrations(0.10,0.20,0.25,0.30,0.40,0.60,0.80,1.00?g/mL)of astaxanthin to the diluent BTS can increase the total antioxidant capacity of the semen. The addition of astaxanthin at a concentration of 1.00?g/mL had the best protection against oxidative damage to semen.The 5-day storage of semen T-AOC was 3.64 nmol/L,the MDA content was 4.02 nmol/mL,and the ROS level was 1066.67.Significantly higher than the control group(P<0.05).However,the addition of 0.25?g/mL astaxanthin could enhance the activity of semen antioxidant enzyme.When the 5 d was stored,the semen superoxide dismutase(SOD)was 9.18 U/mL,and glutathione peroxidase(GSH-Px)was 170.67?mol/L,and catalase(CAT)was 6.99 U/mL,which was significantly higher than that of the control and other test groups(P<0.05).3.The addition of astaxanthin at different concentrations in porcine semen had no significant effect on sperm motility parameters.The linear movement speed(VSL)of spermatozoa in the 0.25?g/mL astaxanthin group increased slightly,but it was different from that in the control group.Not significant(P>0.05);the curve movement velocity(VCL),average path velocity(VAP),and lateral movement amplitude(ALH)were significantly higher on the 5th,3rd,and 1st days than the control group,respectively.(P<0.05).4.Adding different concentrations of astaxanthin to the pig semen can increase sperm energy metabolism.When 0.25?g/mL astaxanthin was added to the diluent,semen ATP levels and lactate dehydrogenase(LDH)activity were significantly increased(P<0.05);0.30?g/mL astaxanthin group had higher mitochondrial membrane potential sperm percentage.When stored to the 5th day,the ATP level was 9.52 nmol/10~8 sperm,and the LDH activity was 2346.67 U/L.In summary,the addition of astaxanthin in the normal temperature preservation diluent of pig semen can improve the preservation quality of semen and the optimum concentration of astaxanthin is 0.25?g/mL.