The Effects Of N-Acetyl-L-Cysteine On The Outcome Of Fixed-timed Atificial Insemination In Pig

The inefficient of reproductive restrict the development and competitiveness of China in the international’s pig industry market.One of the bottlenecks of reproductive inefficiency is the low utilization rate of sows.The technology of fixed-time artificial insemination(FTAI)improve the utilization of sows,but pregnant mare serum gonadotropin(PMSG)could stimulate the follicular development on pigs treated with FTAI,while at the same time affect the receptive of uterus.The aim of this study was to improve the breeding of gilt or sow with supplement NAC into feed following FTAI.At first,superovulation ICR mice treated with PMSG were chosed as modle,result showed that NAC pretreatment could significantly improve implantation sites on day 8 compared with control group(26.92±1.56 vs.22.53±0.50,P<0.05).The number of fetus of recipients on day 11 from NAC pretreatment mice treat with PMSG were similar with PMSG groups(7.50±2.83 vs.7.88±2.55).Compared to PMSG treated recipients,the number of fetus of on day 11 of receipts pretreatment with NAC superovulated mice were significantly increased(8.38±1.93 vs.6.44±2.13,P<0.05),which indicated that NAC improve the environment of uterus of superovulation mice.Further study found that PMSG causes abnormal proliferation of uterine cavity epithelial and gene expression of estrogen receptors abnormal and its downstream molecules such as ERα/Muc1/Ltf,and superovulation mice pretreated with NAC,could significantly inhibit ERα/Muc1/Ltf abnormal expression.Interestingly,NAC pretreatment could alleviate the abnormal effect of PMSG,inhibits the overproliferation of endometrial epithelium,abnormal gene expression of ERα and improve the receptivity of the uterus.On the basis of above,we established the NAC pretreatment program of gilt or sow with FTAI.The gilts were allocated to foour groups after synchronized with altrenagest.Differrent groups of gilts feed with concentrations of respectively 0g/kg,1g/kg,3g/kg,9g/kg of NAC diet until the end of pregnancy test;The sows were allocated to 4 groups after synchronized with wening.Differrent groups of sows feeding with concentration respectively 0g/kg,2g/kg,6g/kg and 18g/kg until the end of pregnancy test.The effect of NAC on the reproductive performance of sows,such as pregnancy rate and litter size,was examined.The results showed that when the NAC concentration in feed was 3g/kg,the pregnancy rate of gilt mating(83.33%vs.73.71%,P<0.05),and the rate of pregnancy delivery(96.55%vs.75.00%,P<0.05),and litter size(11.22±2.33 vs.10.43±2.47,P<0.05)were all significantly increased.When the feed NAC concentration was 2,6g/kg,the total number of litters in the sows(11.32±2.35 vs.10.43±2.36,11.38±2.19 vs.10.43±2.36,P<0.05).The number of alive-born pigs(11.05±2.15 vs.10.10±2.24,P<0.05)and the number of juveniles(10.95±2.12 vs.9.75±2.63,10.92±2.06 vs.9.75±2.24,P<0.05)could be significantly increased,but it didn’t affect the birth weight of piglets,litter weight and so on.It is concluded that PMSG-treatment could cause abnormal expression of ERα and estrogen downstream molecules in endometrium,induce abnormal over-proliferation of lumina epithelial in superovulation mice.However,NAC pretreatments inhibits the ER abnormal expression in uteri of ovulation mice,relieve the abnormal proliferation of lumina endothelium,and improve the environment of uterine pregnancy of PMSG treated mice.In addition,the combination of NAC and FTAI can significantly enhance the reproductive performance of gilts and sows.