| The present study was conducted to investigate the effects of backfat thickness of sows at the end of gestation on lipid deposition and oxidative stress in placenta and litter performance,and thus to explore the relationship between fat deposition and reproductive performance in gestational sows.At 109 d of gestation,backfat thickness of a total of 846 sows was measured and the sows were divided into three groups on the basis of the backfat thickness: ?18 mm for the first group,19 ~ 22 mm for the second group,?23 mm for the third group.The effects of backfat thickness on lipid metabolism,oxidative stress and inflammatory response were studied.The results were as follows:1,Although the number of total born,live litter and mummy were unaffected by the backfat thickness at 109 d of gestation(P>0.05),significant effects for other newborn traits were observed.We found that sows of the second group had significantly higher litter birth weight,birth weight and placental efficiency than those of the other two groups(P<0.05),and had significantly lower number of stillbirth than those of the first group(P<0.05),but with no difference as compared with the third group(P>0.05).It is noteworthy that the number of piglets with a birth weight less than 0.9 kg and 1 kg in the third group were significantly higher than those in the other two groups(P<0.05).The thickness of the backfat also had a significant effect on the lactation performance of the sow.We found that sows of the second group had significantly higher after cross-foster,weaning weight and weaning litter weight than those of the other two groups(P<0.05).And also sows in the third group had the lowest lactation feed intake(P<0.05).2,The analysis between backfat thickness at the end of gestation and sow reproductive performance found that the backfat thickness of not more than 22 mm,the backfat thickness and live litter,total born,litter birth weight,weaning weight had a significant posstive correlation(P<0.05),and had no significant correlation with the effects of birth weight,placental weight and placental efficiency(P>0.05).There was a significant negative correlation between backfat thickness and birth weight,placental efficiency,weaning litter weight and weaning weight when the sows had a thickness of more than 22 mm at the end of gestation(P< 0.05),and had no significant correlation with the live litter,total born,litter birth weight and placental weight.There was no significant correlation between backfat thickness and after cross-foster and lactation feed intake.3,The levels of cholesterol and LDL-C in the third group of sows and umbilical cord were significantly increased(P<0.05),and the levels of triglyceride,LDL-C and FFA in the placenta were also significantly increased(P<0.05),and The expression of mRNA in the placenta was significantly up-regulated(P<0.05).The results of oil red O staining showed that there was a lot of lipid droplets in the third group.4,There was no significant effect of backfat thickness on T-AOC in sow,umbilical cord serum and placental tissue(P>0.05).However,the levels of MDA and ROS in the sow,umbilical cord and placenta in the third group were significantly higher than those those in the other two groups(P<0.05).And SOD activity in the placenta of the third group was significantly lower than that of the other two groups(P<0.05).There was a significant negative correlation between ROS level and total litter size,primary litter weight and placental efficiency(P<0.05).There was a significant negative correlation between MDA level and total litter size(P<0.05).5,The mRNA expression of proinflammatory cytokines IL-1? and IL-6 in the placenta of the third group was significantly up-regulated(P<0.05),and it was positively correlated with backfat thickness(P<0.05).6,The expression of VEGFA mRNA in the second group was significantly higher than that in the other two groups(P<0.05),and the vascular density was positively correlated with placental efficiency,VEGFA mRNA expression and birth weight(P<0.05).In summary,it can be seen that sow fat deposition at the end of pregnancy has a significant impact on reproductive performance.When the sows had a backfat thickness of 19 to 22 mm,the sow had the best reproductive performance and the placental function was normal.When the thickness of the backfat was?18 mm,the number of stillbirths increased.When the thickness of the backfat was more than 22 mm,excessive lipid deposition,the body's lipid levels increased,often resulting in excessive deposition of placental tissue lipid,increased placental oxidative stress and inflammatory response,placental vascular development blocked,resulting in nutrient transport barriers,resulting in a modest increase in the number of weak. |
PDF Full Text Request