| At present,in order to reduce the breeding number of rooster and improve the fertility rate and production efficiency,farmers generally adopt artificial insemination technology to assist chicken breeding.However,with the extension of storage time of semen after collection,the reactive oxygen species(ROS)level increase and sperm is subjected to oxidative stress,which will eventually lead to the decline of its vitality or even apoptosis and directly affect the fertilization rate.Many studies have shown that diluent supplemented with antioxidant can effectively reduce the level of oxidative damage in sperm and help to preserve sperm motility.Therefore,in this research chicken semen extender will be supplemented with astaxanthin,a strong natural antioxidant.And a serial assays were performed to determine the semen quality after preservation under low or room temperature preservation,including the sperm vitality,plasma membrane integrity,ATP content and lactate dehydrogenase(LDH)activity,total antioxidant capacity(T-AOC),level of reactive oxygen species(ROS),malondialdehyde(MDA),superoxide dismutase(SOD),glutathione peroxidase(GSH-PX),catalase(CAT)and fertilization rate.The main results of this study are as follows:Firstly,semen was preserved at low temperature(4℃).The results showed that the extender containing astaxanthin could improve the quality of the cryopreserved semen,the sperm motility(The fifth day,20.73±0.95%),acrosome integrity rate and plasma membrane integrity rate of the head and tail.LDH activity and ATP content of the astaxanthin group were the higher than control(P<0.05).The sperm deformity rate of 0.35 μg/m L astaxanthin group was higher than that of the control group at day 5(P<0.05).The T-AOC,ROS,SOD,GSH-PX,MDA and CAT indexes of semen in the astaxanthin supplementation group were better than in control(P<0.05).The highest fertilization rate was obtained at 0.20 μg/m L(63.25±4.42%).Secondly,semen was preserved at room temperature(25-30℃).The sperm motility(The second day17.43±3.18%),acrosome integrity and plasma membrane integrity of the head and tail,LDH activity and ATP content of the astaxanthin group were the higher than that of control(P<0.05).An optimal index of T-AOC,ROS and MDA were obtained in the astaxanthin addition group(P<0.05).The optimal indexes of SOD GSH-PX and CAT in semen while0.20 μg/m L astaxanthin was supplemented(P<0.05).Artificial insemination was performed using semen diluted immediately after extraction.The fertilization rate of 0.20 μg/m L astaxanthin group was the highest(93.23±4.80%).Finally,a comparison between 0.20 μg/m L astaxanthin diluent and0.2mg/m L lycopene diluent was conducted in this study.The results showed that the sperm plasma membrane integrity rate of the astaxanthin group preserved at low temperature for 5 days was higher than that of the lycopene group(P<0.05),but the CAT activity was lower than that of the lycopene group.There was no significant difference in sperm motility,acrosome integrity rate,T-AOC and ROS between the two groups.Sperm motility(21.43±4.83%),acrosomal and plasma membrane integrity rate,T-AOC were all higher in the astaxanthin group stored at room temperature than in the lycopene group(P<0.05),and CAT activity was lower than that in the lycopene group.There was no significant difference in ROS levels between the two groups.In summary,supplementation of astaxanthin in chicken semen extender can reduce the oxidative stress and thereby improve the quality of semen.The results show that while astaxanthin is added to the extender at optimal concentration of0.20 μg/m L,semen quality and fertilization are improved.Compared with0.2mg /m L lycopene diluent,0.20 μg/m L astaxanthin diluent was added to the sperm plasma membrane integrity and T-AOC parameters.These results suggest feasibility of the use of astaxanthin as antioxidant in the chicken semen preservation. |
