Effects Of PMSG On Reproductive Performance,Serum Reproductive Hormones And Metabolomics In Dairy Goats With Estrus Synchronization Treatment

Xinong Saanen goats has excellent reproductive performance so improve it’s reproductive performance has important significance.Pregnant Mare Serum Gonadotropin（PMSG）can promote follicular development and ovulation,widely used in experimental research and animal production.The study used different doses of PMSG in Xinong Saanen goats with estrus synchronization treatment to investigate the effects of PMSG on the reproductive performance,serum biochemical indexes,reproductive hormones and metabolomics.Fifty-seven dairy goats were randomly divided into 3 groups:control group（n=17）,PMSG 250 IU group（n=20）and PMSG 350 IU group（n=20）.All animals received a Controlled Internal Device Release（CIDR）insert for 12 days.PMSG 250 IU group and PMSG 350 IU group was treated with 250 IU and 350 IU PMSG respectively 48 h before removing CIDR.The following results were obtained through detecting serum biochemical indexes,reproductive hormone and metabolism analysis:1.Effect of PMSG treatment on reproductive performance in dairy goatsThe control group showed estrous manifestations in 36～72 h after CIDR removed and the estrus rate was 82.35%.The PMSG 250 IU group and PMSG 350 IU group showed estrous manifestations in 0～48 h and the estrus rates were 100%（P<0.05）.There were no significant differences in estrus interval,multi-birth,pregnancy rate and litter size between the groups（P>0.05）.The optimal treatment dose of PMSG is 17～20 IU/W^0.75.2.Effect of PMSG treatment on biochemical indexes in dairy goatsThere was no significant difference in biochemical indexes among groups（P>0.05）.Glucose（GLU）of pregnant goats of PMSG 250 IU group was significantly decreased on 21^stday after artificial insemination（AI）（P<0.05）,other groups were not different（P>0.05）;Total Cholesterol（TC）was significantly increased at AI（P<0.05）;Total Protein（TP）in PMSG 250 IU group and pregnant goats of control group decreased significantly on the day of AI（P<0.05）and all groups increased on AI 21^stday（P<0.05）.3.Effect of PMSG treatment on reproductive hormones in dairy goatsConcentration of Follicle stimulating hormone（FSH）in PMSG 350 IU group was higher than other groups on the day of AI.Concentration of FSH in other group decreased gradually with time（P<0.05）.Concentration of Estrogen（E₂）in PMSG 350 IU group was significantly higher than PMSG 250 IU group and control group（P<0.05）.Concentration of E₂increased significantly on the day of AI（P<0.05）.From AI 7^thday,concentration of Progesterone（P₄）in PMSG 350 IU group was higher than PMSG 250IU group,and PMSG250IU group was higher than control group（P<0.05）.Concentration of P₄in each group increased with time gradually（P<0.05）.4.Serum metabolism analysis between control group and PMSG group on AI 21^stdayIn the pregnant groups,17 plasma differential metabolites were screened in total,of which 7 were down-regulated and 10 were up-regulated.The different metabolites are mainly enriched in thermogenesis pathway,arginine biosynthesis pathway and so on.In the non-pregnant groups,14 plasma differential metabolites were screened in total,of which 10 were down-regulated and 4 were up-regulated.The different metabolites are mainly enriched in m TOR signaling pathway,Arginine biosynthesis pathway and so on.5.Serum metabolism analysis between pregnant and non-pregnant goats on AI 21^st dayIn the control group,18 plasma differential metabolites were screened in total,of which13 were down-regulated and 5 were up-regulated.The different metabolites are enriched in fatty acid biosynthesis pathway,biosynthesis of unsaturated fatty acids pathway and so on.In the PMSG group,34 plasma differential metabolites were screened in total,of which19 were down-regulated and 15 were up-regulated.The different metabolites are mainly enriched in arginine biosynthesis pathway,mineral absorption pathway and so on.Compared with non-pregnant goats,Arg-Gln was up-regulated and acetylcarnitine was down-regulated in serum of pregnant goats（P<0.05）,which are associated with pregnancy.In conclusion,the groups treated with PMSG had higher estrus rate（P<0.05）and there were no significant differences on estrus interval,pregnancy rate and litter size between the groups（P>0.05）;PMSG can significantly increase the levels of P₄and E₂and the optimal treatment dose is 17～20 IU/W^0.75;PMSG can significantly increase the levels of carnitine and acylcarnitine compounds in serum of dairy goats,and affect the reproductive ability of dairy goats through arginine synthesis signaling pathway or m-TOR signaling pathway.Pregnancy is closely related to lipid metabolism,Arg-Gln and acetylcarnitine may be considered biomarkers for the diagnosis of pregnancy in dairy goats.The study analyzed the effects of PMSG on the reproductive performance in dairy goats from many angles,which provided a theoretical basis for optimizing the application of estrus synchronization in animal husbandry and lead a foundation for the rapid development of dairy goat industry.