Effect And Mechanism Of Maternal Yeast-based Nucleotides Supplementation On Intestinal Barrier Of Neonatal Pigs And Nutrient Transport Of Placenta

Yeast-based nucleotides(YN)are an enzymatic product of yeast,and it is rich in nucleotides.In this study,we aimed to evaluate the effect and mechanism of maternal YN supplementation during late pregnancy and lactation on small intestinal physical and immune barrier of neonatal pigs and nutrient transport of placenta.Sixty pregnant sows(day 80 ± 3)were assigned to two groups based on parity: the CON group(fed a basal diet)and YN group(fed a basal diet with 4 g YN / kg diet).The experiment is conducted at 80 d after pregnancy of sows until weaning of suckling piglets.Placental samples were obtained during sow delivery,plasma and intestinal samples of neonatal piglets were obtained immediately after birth.In addition,the daily gain(ADG)and diarrhea rate of suckling piglets were recorded.The serum D-lactic acid and diamine oxidase of neonatal piglets were detected by biochemical kits.The intestinal morphology of neonatal piglets was observed by the HE staining.The mRNA expression level of intestinal tight junction protein and cytokine in neonatal piglets were detected by Quantitative real time-polymerase chain reaction(RT-PCR).RT-PCR was used to study placental mRNA expression level of transporters.Western blotting(WB)was used to study placental protein expression associated with mTORC1-PPARs signalling pathway.The results were showed as follows:(1)Compared to the CON group,maternal YN supplementation significantly increased the number of born alive,and decreased stillbirths rate and IUGR rate(P<0.05);in addition,maternal YN supplementation during late pregnancy and lactation significantly decreased diarrhea rate of suckling piglets,and increased the number of weaned piglets and their average weight(P < 0.05).(2)Compared with those in CON group,the villus height of ileum in neonatal piglets from YN group increased by15.82%,and the V/C(the ratio of the height of the villus and crypt depth)in ileum increased by 19.10%(P < 0.01)in neonatal piglets.(3)Compared with those of the CON group,maternal YN supplementation during late pregnancy inhibited mRNA expression of claudin-1 in the duodenum and jejunum,and decreased ZO-1 expression in the jejunum and ileum in neonatal piglets(P < 0.05).(4)An up-regulation of mRNA expression of innate immunity-related genes,such as those encoding interleukin(IL)-17,IL-6,IL-8,IL-1?,and tumour necrosis factor-?(TNF-?),was observed in the jejunum and ileum of neonates from the YN group relative to those of the neonates from the CON group(P < 0.05).(5)Compared to the CON group,maternal YN supplementation significantly increased mRNA expression of SLC28A3 and PPARa in placenta(P<0.01).In addition,the placental mRNA expression of PPAR??EAAT3?PAT1?LAT1 in YN group were decreased(P<0.05);in addition,maternal YN supplementation significantly decreased the phosphorylation of AKT and mTORC1 protein,AKT and PPAR? protein,respectively(P<0.05).In conclusion,maternal YN supplementation during late pregnancy and lactation decreased stillbirth rate,IUGR and diarrhea rate of piglets,and improved the growth performance of piglets;maternal YN supplementation during late pregnancy improved the intestinal physical barrier by increasing the villus height and V/C of ileal in naonatal piglets,and improved the intestinal immune barrier by regulating the mRNA expression of IL-17,IL-8,IL-10,IL-1 ?,TNF-a and other immune-related cytokines in the small intestine of naonatal piglets,which are beneficial to promote intestinal development;maternal YN supplementation during late pregnancy regulated placental nutrient transport by mTORC1-PPARs signalling pathway,which may promote the intestinal development of fetal pigs during late pregnancy to some extent.