Effects Of Administering Exogenous Spermine To Pregnant Sows On The Development Of Fetus And Its Main Appendages

Placenta and umbilical cord are the important organs for material exchanges between fetuses and their mother.It is of great value to study the development of placenta and umbilical cord for the improvement of sow’s reproductive performance.Spermine is one of the endogenous basic polyamines,which is involved in the regulation of gene expression,cell proliferation,cell differentiation and apoptosis.The purpose of this study was to investigate the effects of administering exogenous spermine to pregnant sows on the development of placenta,umbilical cord and fetuses.Twelve sows with the similar parity,back fat and body weight were mated to a boar at the same time,then randomly divided into 4 groups,with 3 pigs in each group.One group is a control group and is fed a basic diet;the other three groups are treatment groups and fed a basic diet supplemented with exogenous spermine 4 mg/kg,6 mg/kg and 8 mg/kg,respectively.The trial period lasted 30 days,from 30^th day to 60^th day pregnancy.On the 60^thday,the sows were slaughtered,the placenta,umbilical cord,and fetal phenotype data were measured.Placental tissues were collected for immunohistochemistry and gene protein expression determination.The test results are as follows:（1）Compared with the control group,4 mg/kg exogenous spermine significantly reduced the placenta area（P<0.05）;6mg/kg exogenous spermine significantly increased the placenta weight（P<0.05）;4 mg/kg,6 mg/kg and 8 mg/kg exogenous spermine significantly increased fetal weight（P<0.05）.（2）Compared with the control group,4 mg/kg,6 mg/kg and 8 mg/kg exogenous spermine significantly increased the umbilical cord length and the outer diameter of the umbilical cord（P<0.05）;kg and 8 mg/kg exogenous spermine significantly increased the outer diameter of umbilical vein and outer diameter of umbilical artery（P<0.05）.（3）Compared with the control group,4 mg/kg and 6 mg/kg exogenous spermine can significantly increase the microvessel density of placental tissue（P<0.05）.（4）Compared with the control group,6mg/kg and 8 mg/kg exogenous spermine significantly increased the m RNA expression levels of placental growth factor（Pl GF）and angiopoietin（ANG）（P<0.05）;4 mg/kg,6 mg/kg and8 mg/kg exogenous spermine significantly increased the protein expression levels of vascular endothelial growth factor（VEGF）,fibroblast growth factor 2（FGF2）and Pl GF（P<0.05）;6 mg/kg and 8 mg/kg exogenous spermine significantly increased the protein expression level of ANG（P<0.05）;exogenous spermine at 6 mg/kg significantly reduced the m RNA expression level of pro-apoptotic factor BAX（P<0.05）;8 mg/kg exogenous spermine significantly reduced the copper and zinc superoxide dismutase（Cu Zn-SOD）m RNA expression level（P<0.05）;4 mg/kg,6 mg/kg and 8 mg/kg exogenous spermine significantly increased the m RNA expression level of glucose transporter gene（P<0.05）;the addition of exogenous spermine to VEGFA,FGF2,B-cell lymphoma-2（Bcl-2）and catalase（CAT）m RNA expression levels no significant effect（P>0.05）.In summary,dietary exogenous spermine may promote the growth and development of placental umbilical cord blood vessels and fetuses by increasing the expression of angiogenesis and angiogenesis-related genes,reducing apoptosis of placental tissue cells,and increasing placental glucose transport in pregnant sows.Feeding pregnant sows with a diet containing 6 mg/kg exogenous spermine has a significant effect on improving the development of the placenta and umbilical cord.