Study On The Effect And Mechanism Of NCG On The Pregnancy Rate Of Goats

Guizhou White Goat is a high-quality local breed in Guizhou Province,which is an ideal model for studying goat reproductive traits.Studies have shown that NCG can promote the synthesis of essential amino acids,thus promoting the growth and development of female animal placenta.Therefore,122 multiparous ewes were divided into NCG group(44),blank group(42)and control group(36).NCG group and blank group were treated with sponge suppository and PMSG at the same time,while the control group did not do any treatment(NATURAL estrus,RAM self-made),and were divided into three groups: NCG group(basal diet + 0.15% NCG),blank group Group A(basal diet),control group(basal diet),NCG was supplemented for 30 days.Blood was collected from jugular vein at 0,15,30 days after NCG feeding.The contents of NO and Arg in serum were detected by ELISA double antibody sandwich method.Three pregnant ewes from NCG group and blank group were slaughtered and collected for gonadal axis tissue.The mRNA expression levels of ITGB8 and IGFBP3 genes in gonadal axis tissue were detected by fluorescence quantitative PCR.The uterus was collected and cultured,and endometrial stromal cells were added into cell culture medium NCG was added to group culture(blank group,blank group + NCG,blank group + E2/P4,blank group + E2/P4 + NCG).CCK-8 reagent was used to detect the growth rate of each group,and fluorescent quantitative PCR was used to detect the mRNA expression levels of ITGB8 and IGFBP3 in each experimental group.The results are as follows:1.Compared with the blank group,the contents of no and Arg in serum of NCG group were significantly increased on the 15 th day(P <0.05).On the 30 th day,the content of Arg in NCG group was significantly higher than that in blank group(P <0.01),while the content of no was only significantly different between NCG group and blank group(P <0.05).Compared with the blank group and the control group,the conception rate of NCG group increased by 13.27% and15.83%,respectively,but the difference was not significant(P >0.05).The average number of lambs in NCG group was significantly higher than that in control group(P <0.05).Compared with blank group and control group,the average number of lambs in NCG group increased by 0.20 and0.36 respectively.The results showed that feeding 0.15% NCG during the first trimester of pregnancy may increase the synthesis of NO and Arg in goats,and the mean litter size and conception rate of goats may be increased by simultaneous ovulation and regular insemination and supplementary feeding of NCG in early pregnancy.2.The expression of ITGB8 and IGFBP3 gene in gonadal axis of Guizhou White Goat was detected by fluorescence quantitative PCR.The results showed that the expression of itgb8 gene in pituitary,ovary,oviduct and uterus in NCG group was significantly higher than that in blank group(P <0.01);the expression of IGFBP3 gene in the above four tissues was significantly lower in NCG group than that in blank group(P <0.01)The expression of the two genes in hypothalamus did not reach a significant level(P >0.05).The results showed that 0.15% NCG could increase the expression of ITGB8,but inhibit the expression of IGFBP3.3.The expression levels of ITGB8 and IGFBP3 in endometrial stromal cells cultured in different media were compared and analyzed.The results showed that the expression of ITGB8 gene in the blank group + E2/P4 + NCG group was significantly higher than that in the blank group(P <0.01),but there was no significant difference among the other groups(P >0.05).There was no significant difference in IGFBP3 gene expression among the experimental groups(P >0.05).The results of CCK-8 assay showed that the cell proliferation in blank group + E2/P4 +NCG group was significantly higher than that in blank group at 24 and 48 h(P <0.05),but there was no significant difference in growth among other experimental groups(P >0.05).In vitro cultured endometrial stromal cells,adding a certain concentration of NCG in the culture medium can promote the proliferation of endometrial stromal cells,and also promote the expression of reproduction related gene ITGB8,which can inhibit the expression of IGFBP3 gene to a certain extent.In conclusion,NCG supplementation in early pregnancy may be beneficial to goat embryo implantation and embryo growth and development,so as to improve goat reproductive performance.