Effect Of Dietary Resveratrol On Reproductive Performance Of Sows In Late Pregnancy

During pregnancy in sows,especially the late gestational period that fetus grows rapidly,the mother undergoes substantial metabolic changes,which can induce inflammation,oxidative stress,and insulin resistance to play a negative effect on the mother and fetus.Alleviating oxidative stress,inflammation and insulin resistance during late pregnancy can potentially improve placental function and reproductive performance of sows.Resveratrol(RES)is a non flavonoid polyphenolic compound that widely exists in plants such as polygonum cuspidatum,berries and peanuts.Our previous study found that dietary resveratrol supplementation can promote placental circulation in pregnant mice,and this study aimed to investigate the effect of dietary resveratrol on placental function and reproductive performance in sows during late pregnancy,and further explore the potential mechanisms from the aspects of inflammation,oxidative stress,insulin resistance and gut microbiota.A total of 26 hybrid pregnant sows(PIC)with similar parity were selected and randomly divided into two groups consisting of 13 replicates each and one sow in each replicate,the control group was fed a basal diet,and another group was fed a diet containing s 200 mg/kg resveratrol based on our previous study.The trial lasted from the 85 th day of pregnancy to delivery.The results showed that :(1)Dietary resveratrol supplementation decreased the number of stillborn foetus,increased the number of live litters by 8.33%,increased the litter weight of piglets by 14.32%,and enhanced the average weight of piglets by 6.77%,but there was no statistically significant difference;(2)Resveratrol significantly increased insulin sensitivity(HOMA-IS),alleviated insulin resistance(HOMA-IR)in sows(P < 0.01),and increased serum triglyceride(TG)level(P < 0.05);(3)Resveratrol significantly reduced serum levels of interleukin-1β(IL-1β)and interleukin-6(IL-6)(P <0.05),but had no significant effect on the levels of reproductive hormones including follicle stimulating hormone(FSH),prolactin(PRL)and progesterone(PROG)in serum;(4)Resveratrol significantly increased placental vascular density and promoted the expression of placental nutrient transport related genes including SLC2A1 and SLC2A3(P < 0.05);(5)Resveratrol significantly increased the expression of superoxide dismutase 2(SOD2)and heme oxygenase 1(HO-1),but decreased the expression of inflammatory cytokines including IL-1β and IL-6 in placenta(P < 0.05);(6)Analysis on gut microbiota showed that resveratrol significantly decreased the relative abundance of the Christensenellaceae family as well as the genera Christensenellaceae R-7 group and Ruminococcaceae UCG-005(P <0.05).Correlation analysis revealed that Christensenellaceae R-7 group and Ruminococcaceae UCG-005 had a positive linear correlation with IL-1β and IL-6 levels(P<0.05)but had a negative linear correlation with the expression of SLC2A1 and SLC2A3(P<0.05),moreover,Christensenellaceae R-7 group had a negative linear correlation with the expression of SOD2 and HO-1(P<0.05).In conclusion,dietary supplementation of 200 mg/kg resveratrol in late pregnancy can reduce the number of stillbirths,alleviate insulin resistance and inflammatory response in sows,and increase placental vascular density with up-regulating the expression of nutrient transport related genes.Additionally,resveratrol can promote the expression of antioxidant genes and inhibit inflammatory cytokines expression in placenta.Analysis on gut microbiota indicated that decreased relative abundance of Christensensllaceae R-7 group and Ruminococcaceae UCG-005 genus are significantly associated with the decreased levels of inflammatory cytokines as well as increased expression of nutrient transport related genes and antioxidant enzyme genes in placenta.