Changes in progenitors and differentiated epithelial cells of neonatal piglets

This study aimed to assess the changes of small intestinal morphology,progenitors,differentiated epithelial cells,and potential mechanisms in neonatal piglets.Hematoxylin and eosin staining of samples from 36 piglets suggested that dramatic changes were observed in the jejunum crypts depth and crypt fission index of neonatal piglets(P<0.001).The number of intestinal stem cells(ISC)tended to increase(P<0.10),and a decreased number of enteroendocrine cells appeared in the jejunal crypt on d 7(P<0.05).Furthermore,the mRNA expression of jejunal chromogranin A(ChgA)was down-regulated in d 7 piglets(P<0.05).There was an up-regulation of the adult ISC marker gene of SPARC related modular calcium binding 2(Smoc2),and Wnt/b-catenin target genes on d 7(P<0.05).These results were further verified in vitro enteroid culture experiments.A mass of hollow spheroids was cultured from the fetal intestine of 0-d-old piglets(P<0.001),whereas substantial organoids with budding and branching structures were cultured from the intestine of 7-d-old piglets(P<0.001).The difference was reflected by the organoid budding efficiency,crypt domains per organoid,and the surface area of the organoid.Furthermore,spheroids on d 0 had more Ki67-positive cells and enteroendocrine cells(P<0.05)and showed a decreasing trend in the ISC and goblet cells(P<0.10).Moreover,the mRNA expression of spheroids differed markedly from that of organoids,with low expression of intestinal differentiation gene(Lysozyme;P<0.05),epithelial-specific markers(Villin,E-cadherin;P<0.05),and adult ISC markers(leucine-rich repeat-containing G protein-coupled receptor 5[Lgr5],Smoc2;P<0.001),and upregulation of fetal marker(connexin 43[Cnx43];P<0.05).The mRNA expression of relevant genes was up-regulated,and involved in Wnt/b-catenin,epidermal growth factor(EGF),Notch,and bone morphogenetic protein(BMP)signaling on d 7 organoids(P<0.05).Spheroids displayed low differentiated phenotype and high proliferation,while organoids exhibited strong differentiation potential.These results indicated that the conversion from the fetal progenitors(spheroids)to adult ISC(normal organoids)might largely be responsible for the fast development of intestinal epithelial cells in neonatal piglets.

Maternal pyrimidine nucleoside supplementation regulates fatty acid,amino acid and glucose metabolism of neonatal piglets

Pyrimidine nucleosides(PN)are abundant in mammalian milk and mainly involved in glycogen deposition and lipid metabolism.To investigate the effects of maternal supplementation with pyrimidine nucleoside on glucose,fatty acids(FAs),and amino acids(AAs)metabolism in neonatal piglets.Forty pregnant sows were randomly assigned into the control(CON)group(fed a basal diet,n=20)or the PN group(fed a basal diet supplemented with PN at 150 g/t,n=20).Litter size,born alive and birth litter weight were recorded.The serum and placenta of sows,and jejunum and liver of neonatal piglets were sampled.The results indicated that supplementing sow diets with PN decreased birth mortality and increased the birth weight of piglets(P<0.05).In addition,neonates from sows supplemented with PN had higher glucose levels in serum and liver compared with the CON group(P<0.05).Moreover,maternal PN supplementation regulated the ratio of saturated FAs and polyunsaturated FAs,and AAs content in serum and liver of piglets(P<0.05).Furthermore,an up-regulation of m RNA expression of genes related to glucose and AA transport were observed in the neonatal jejunum from the PN group(P<0.05).Additionally,hepatic protein expressions of phosphorylated hormone-sensitive lipase(P-HSL),HSL,sterol regulatory element-binding transcription factor 1c(SREBP-1c),and phosphorylated protein kinase B(P-AKT)was higher in the piglets from the PN group than the CON group(P<0.05).Together,maternal PN supplementation may regulate nutrient metabolism of neonatal piglets by modulating the gene expression of glucose and AA transporters in placenta and jejunum,and the gene and protein expression of key enzymes related to lipid metabolism in liver of neonatal piglets,which may improve the reproductive performance of sows.

Yeast-based nucleotide supplementation in mother sows modifies the intestinal barrier function and immune response of neonatal pigs

In the present study,we aimed to evaluate the effects of maternal yeast-based nucleotide(YN)sup-plementation on the intestinal immune response and barrier function in neonatal pigs,as well as the diarrhoea rate and growth performance in suckling piglets.Sixty-four late-gestation sows were assigned to the following groups:the CON(fed a basal diet)and YN groups(fed a basal diet with 4 g YN/kg diet).The experiment started on d 85 of gestation and ended on d 20 of lactation.Diarrhoea rate and average daily gain of the piglets were recorded,and samples of blood and intestines from neonatal piglets were collected before they consumed colostrum during farrowing.Compared with the CON group,maternal YN supplementation increased the weaning weight of litter and decreased the diarrhoea rate(P<0.01).In addition,maternal YN supplementation promoted the ileal villus development in the neonates compared with that in the CON group(P<0.01).Maternal YN supplementation also increased the ileal secretory immunoglobulin A(sIgA)level compared with that in the CON group(P<0.05).The real-time PCR results showed that maternal dietary YN supplementation increased the jejunal and ileal expression of interleukin(IL)-17,IL-8,IL-1β,IL-10 and tumor necrosis factor(TNF)-αin the neonates compared with that in the CON group(P<0.05).Overall,maternal nucleotide supplementation improved the villus development and innate immunity of neonatal piglets during late pregnancy.This may be associated with the decrease in diarrhoea and the increase in weaning weight of the litter of suckling piglets.