The Metabolism Of Bile Acid And Its Effect On Sows Reproductive Performance From Middle To Late Gestation

Death piglets which included stillbirth and mummies was a prominent problem that faced by sows,which limit sows reproductive performance and production benefit,but the recognition of death piglets mechanism was scare.Many studies have showed that maternal occurred bile acid metabolism disorder in the second or third trimester,which brought about raised serum total bile acid level,leading to adverse fetal outcome,such as preterm delivery,respiration distress,fetal death and so on.The bile acid level increased abnormally was more often in twin pregnancies than singleton pregnancies.As multiparous births animal,pigs have the similar anatomical structure and physiological feature with human,including digestive system,cardiovascular system and so on,whether sows could occur bile acid metabolism disorder from middle to late gestation.Therefore,this experiment was conducted to establish brachiocephalic vein catheterization,exploring the bile acid metabolism from middle to late gestation,explicating the relationship between the bile acid metabolism with fetal survival rate.Experiment one The time period effect of death piglets and establishment of sows brachiocephalic vein catheterizationEighteen crossbred gilts((LandracexYorkshine)were selected,which have similar body weight(127.34±1.65kg),age(210.0±7.0d)and in good health.sows were fed at the same condition and same diet and bred at the third estrus.Six sows were anaesthetized by obstetrics anesthesia,and caesarean were conducted to record fetal body weight and survival condition.The remaining twelve sows were installed brachiocephalic vein catheterization by inhaled anesthesia at the right side,brachiocephalic vein catheterization were washed twice daily which were conducted at morning and afternoon.On day 90 of gestation,six sows were anaesthetized by obstetrics anesthesia,and caesarean were conducted to record fetal body weight and survival condition.The remaining six sows were fed till spontaneous delivery and recorded the farrowing condition.The results showed that:(1)On day 60,90 of gestation and natural delivery,the average litter size were 13.33,13.20 and 13.00,respectively;death piglets rate were 0.00%,1.52%and 6.41%,respectively.Death piglets rate on natural delivery day was higher than day 60 of gestation(P<0.05);average live litter weight were 144.23,649.22and 1302.13g,respectively.there was significant difference between the two(P<0.01).(2)From day 60 of gestation when the brachiocephalic vein catheterization were installed to day 90 of gestation or parturition,sows were kept healthy,the brachiocephalic vein catheterization could blooding all the time.The above results showed that there was a time period effect of death piglets from middle to late gestation,day 90 of gestation to parturition was the frequent occurrence periods of death piglets;fetal body gain and death piglets rate were in agreement with previous studies of our research group,the results implying brachiocephalic vein catheterization operation and maintaining have no effect on fetus growth and survival,and brachiocephalic vein catheterization could blooding all the time.Therefore,we have successfully established the brachiocephalic vein catheterization of sows.Experiment two The metabolism of bile acid and its effect on sows farrowing performance from middle to late gestationTwelve crossbred gilts((Landrace×Yorkshine)were selected,which have similar body weight(125.97±2.34kg),age(210.0±7.0d)and in good health.Sows were fed at the same condition and diet and bred at the third estrus.sows were anaesthetized by obstetrics anesthesia,and brachiocephalic vein catheterization were installed on day 60 of gestation,the fasting blood sample were collected among day 60,68,75,82,90,97,105 and 114 of pregnancy,respectively.On day 90 of gestation,the brachiocephalic vein blood were collected dynamically in 0,2,4,6 and 8 h,respectively,the 0h means overnight fasting.The farrowing performance was recorded on parturition.The results showed that:(1)The varying pattern of serum bile acid level:the total bile acid level(TBA) was increased slowly from day 60 to 75 of gestation,then increased sharply from day 75 to 90 of gestation,later decreased from day 90 to 105 of gestation;the total bile acid level on day 75 of gestation(14.32±1.41?mol/L)was significant higher than day 60 of gestation(8.40±1.50?mol/L)(P<0.05),the total bile acid level on day 90 of gestation(30.42±5.29?mol/L)was higher than day 75 and 105 of gestation(11.78±2.38?mol/L)(P<0.05),respectively.There was no significant difference of total bile acid level on day 60,68,105 and 114 of gestation(P>0.05).(2)The effect of serum bile acid ratio(the ratio of total bile acid level between day 90 with 60 of gestation)on farrowing performance:As for death piglets rate,sows whose ratio no less than 3 was significant higher than sows whose ratio lower than 3(20.80%vs 8.20%,P<0.05),sows whose ratio no less than 6 was significant higher than sows whose ratio lower than 6(28.60%vs 11.80%,P<0.05);As for litter size and live litter size,sows whose ratio no less than 3 was significant lower than sows whose ratio lower than 3(9.63 and 7.63 vs 15.25 and 14.00,P<0.05);As for litter weight and live litter weight,sows whose ratio no less than 3 was significant lower than sows whose ratio lower than 3(11.44 and 9.89 vs 17.02 and 16.39,P<0.05);As for average litter weight,there was no significant difference between sows whose ratio no less than 3 with sows whose ratio lower than 3(P>0.05).(3)The varying pattern of postprandial serum bile acid:when the serum total bile acid ratio(the ratio of total bile acid level between day 90 with 60 of gestation)was 3,in 0h postprandial of day 90 of gestation,the serum total bile acid level of sows whose ratio no less than 3 was significant higher than sows whose ratio less than 3(P<0.05);the serum total bile acid level of sows whose ratio less than 3 was increased sharply in 2h postprandial,and decreased after 2h,the serum total bile acid level in 2h was significant higher than 0h(16.57±2.37?mol/L)and 8h(22.96±5.65?mol/L)(P<0.05),respectively;there was no significant difference between 8h and 0h(P>0.05).On the contrary,the serum total bile acid level of sows whose ratio no less than 3 have no obvious change,there was no significant difference in 0,2,4,6 and 8h postprandial(P>0.05).The results above showed that:sows could occur bile acid metabolism disorder during late gestation,the total bile acid ratio between day 90 with 60 of gestation no less than 3 have adverse effect on fetus survival,the postprandial bile acid metabolism disorder may the reason of this phenomenon.In conclusion:we have successfully established the brachiocephalic vein catheterization of sows,revealing the varying pattern of serum bile acid level from middle to late gestation,discovering late gestation was the frequent occurrence periods of death piglets,confirming death piglets was closely related to bile acid metabolism disorder,proposing maintain homeostasis of bile acid metabolism have important meaning to raise fetal survival rate.