Fetal and neonatal programming of postnatal growth and feed efficiency in swine

Maternal undernutrition or overnutrition during pregnancy alters organ structure, impairs prenatal and neonatal growth and development, and reduces feed efficiency for lean tissue gains in pigs. These adverse effects may be carried over to the next generation or beyond. This phenomenon of the transgenerational impacts is known as fetal programming, which is mediated by stable and heritable alterations of gene expression through covalent modifications of DNA and histones without changes in DNA sequences(namely, epigenetics). The mechanisms responsible for the epigenetic regulation of protein expression and functions include chromatin remodeling; DNA methylation(occurring at the 5′-position of cytosine residues within CpG dinucleotides); and histone modifications(acetylation, methylation, phosphorylation, and ubiquitination). Like maternal malnutrition, undernutrition during the neonatal period also reduces growth performance and feed efficiency(weight gain:feed intake; also known as weightgain efficiency) in postweaning pigs by 5–10%, thereby increasing the days necessary to reach the market bodyweight. Supplementing functional amino acids(e.g., arginine and glutamine) and vitamins(e.g., folate) play a key role in activating the mammalian target of rapamycin signaling and regulating the provision of methyl donors for DNA and protein methylation. Therefore, these nutrients are beneficial for the dietary treatment of metabolic disorders in offspring with intrauterine growth restriction or neonatal malnutrition. The mechanism-based strategies hold great promise for the improvement of the efficiency of pork production and the sustainability of the global swine industry.

Glycine represses endoplasmic reticulum stress-related apoptosis and improves intestinal barrier by activating mammalian target of rapamycin complex 1 signaling

Endoplasmic reticulum(ER)stress has been associated with the dysfunction of intestinal barrier in humans and animals.We have previously shown that oral administration of glycine to suckling-piglets improves ER stress-related intestinal mucosal barrier impairment and jejunal epithelial apoptosis.However,the underlying mechanism remains unknown.In this study,the protective effect and the mechanism of glycine on apoptosis and dysfunction in intestinal barrier induced by brefeldin A(BFA),an ER stress inducer,was explored in porcine intestinal epithelial cells(IPEC-1).The results showed that BFA treatment led to enhanced apoptosis and upregulation of proteins involved in ER stress signaling,including inositol-requiring enzyme 1a(IRE1a),activating transcription factor 6a(ATF6a),c-Jun N-terminal kinase(JNK),and C/EBP-homologous protein(CHOP).In addition,BFA induced a dysfunction in intestinal epithelial barrier,as evidenced by the increased paracellular permeability,decreased transepithelial electrical resistance(TEER),and reduced abundance of tight junction proteins(occludin,claudin-1,zonula occludens[ZO]-1,and ZO-2).These alterations triggered by BFA were significantly abolished by glycine treatment(P<0.05),indicating a protective effect of glycine on barrier function impaired by ER stress.Importantly,we found that the regulatory effect of glycine on intestinal permeability,proteins implicated in ER stress and apoptosis,as well as the morphological alterations of the ER were reversed by rapamycin.In summary,our results indicated that glycine alleviates ER stress-induced apoptosis and intestinal barrier dysfunction in IPEC-1 cells in a mammalian target of rapamycin complex 1(mTORC1)-dependent manner.The data provides in vitro evidence and a mechanism for the protective effect of glycine against the disruption of intestinal barrier integrity induced by ER stress.

Flavor supplementation during late gestation and lactation periods increases the reproductive performance and alters fecal microbiota of the sows

This study was conducted to evaluate the effect of flavor on reproductive performance and fecal microbiota of sows during late gestation and lactation.A total of 20 healthy Yorkshire sows were fed a corn-soybean basal diet unsupplemented or supplemented with 0.1%flavor compound from d 90 of gestation to 25 d post-farrowing,and then the piglets were weaned.The reproductive performance and the fecal microbiota of sows were analyzed.Compared with the controls,flavor supplementation in maternal diets increased(P<0.05)weaning litter weight,litter weight gain,weaning body weight,and average daily gain of piglets.There was a trend of increase in the average daily feed intake of sows(P=0.09)by maternal dietary flavor addition.The backfat thickness and litter size were not affected by flavor supplementation(P>0.05).The 16S rRNA analysis showed that flavor supplementation signifi-cantly increased the abundance of Phascolarctobacterium(P<0.05),but significantly decreased genera Terrisporobacter,Alloprevotella,Clostridium_sensu_stricto_1,and Escherichia-shigella(P<0.05).Spearman correlation analysis showed that Phascolarctobacterum was positively correlated with the average daily feed intake of sows(P<0.05),the litter weight gain and average daily gain of piglets(P<0.05).In contrast,Clostridium_sensu_stricto_1 and unclassified_f__Lachnospiraceae were negatively correlated with the litter weight gain and average daily gain of piglets(P<0.05).Taken together,dietary flavor sup-plementation improved the reproductive performance of the sows,which was associated with enhanced beneficial microbiota and decreased potentially pathogenic bacteria in the sows.