The Protective Effects Of Different Types Of Antioxidants On Frozen-thawed Boar Sperm

As boar sperm is sensitive to oxidative stress,suitable antioxidants are still needed to find out for improving the frozen-thawed sperm quality.Spermine,lentinan,apigenin and ferulic acid were all demonstrated to be high-efficiency antioxidants and never used to protect sperm from cryodamage before.The main aim of the present study was to evaluate the cryoprotective effect of spermine,lentinan,apigenin and ferulic acid on boar sperm during cryopreservation.With this purpose,semen samples coming from 5 Landrace boars were used in this study.Ejaculates of five boars were mixed and split into several aliquots,in which different doses of spermine,lentinan,apigenin and ferulic aicd were added separately or together.The motility,the plasma membrane integrity,the mitochondrial activity,the acrosomal integrity,the antioxidase(SOD and CAT)activities and the malondialdehyde(MDA)concentration of the frozen-thawed boar sperm were assessed,respectively.The results were as follows:1.The motility,the plasma membrane integrity,the mitochondrial activity,the acrosomal integrity and the antioxidase(SOD and CAT)activities of the frozen-thawed boar sperm were significantly improved and the MDA concentration was significantly declined by the supplement of spermine(P < 0.05),and the optimal additive concentration was 3 mM.Howere,the improvement can’t last for 2 h.2.The motility,the plasma membrane integrity and the acrosomal integrity of the frozen-thawed boar sperm were significantly improved and the MDA concentration was significantly declined by the supplement of lentinan(P < 0.05),and the optimal additive concentration was 0.6-0.9 mg/mL.However,lentinan can’t help improve the mitochondrial activity and the the antioxidase(SOD and CAT)activities.3.The motility,the plasma membrane integrity,the mitochondrial activity,the acrosomal integrity and the antioxidase(SOD and CAT)activities of the frozen-thawed boar sperm were significantly improved and the MDA concentration was significantly declined by the supplement of either apigenin or ferulic aicd(P < 0.05).The optimal additive concentration of apigenin was 0.2 mM and the optimal additive concentration of ferulic acid was 0.25 mM.4.Supplementation of freezing extender with both apigenin and ferulic acid had a combined,beneficial effect on frozen-thawed boar sperm.The quality of the frozen-thawed boar sperm was further improved(P < 0.05)and the optimal additive concentration was 0.1 mM apigenin plus 0.15 mM ferulic acid.At this concentration,the motility evaluated at 2 h didn’t decrease significantly compared with that evaluated at 0.5 h,which might cater to the request of artificial fertilization.5.Lentinan,apigenin and ferulic acid could help improve the fertilization ability of the frozen-thawed boar sperm at each optimal concentration,which could be reflected in the cleavage rate.When supplied with 0.6mg/mL of lentinan,0.1 mM of apigenin and 0.15 mM ferulic acid together,the cleavage rate was significantly higher than that of other treatment groups(P < 0.05).