Membrane proteomic analysis reveals the intestinal development is deteriorated by intrauterine growth restriction in piglets

Effects of maternal methyl donor intake during pregnancy on ileum methylation and function in an intrauterine growth restriction pig model

BACKGROUND

Intrauterine growth retardation (IUGR) affects intestinal growth, morphology, and function, which leads to poor growth performance and high mortality. The present study explored whether maternal dietary methyl donor (MET) supplementation alleviates IUGR and enhances offspring's growth performance by improving intestinal growth, function, and DNA methylation of the ileum in a porcine IUGR model.

METHODS

Forty multiparous sows were allocated to the control or MET diet groups from mating until delivery. After farrowing, 8 pairs of IUGR and normal birth weight piglets from 8 litters were selected for sampling before suckling colostrum.

RESULTS

The results showed that maternal MET supplementation tended to decrease the IUGR incidence and increased the average weaning weight of piglets. Moreover, maternal MET supplementation significantly reduced the plasma concentrations of isoleucine, cysteine, urea, and total amino acids in sows and newborn piglets. It also increased lactase and sucrase activity in the jejunum of newborn piglets. MET addition resulted in lower ileal methionine synthase activity and increased betaine homocysteine S-methyltransferase activity in the ileum of newborn piglets. DNA methylation analysis of the ileum showed that MET supplementation increased the methylation level of DNA CpG sites in the ileum of newborn piglets. Down-regulated differentially methylated genes were enriched in folic acid binding, insulin receptor signaling pathway, and endothelial cell proliferation. In contrast, up-regulated methylated genes were enriched in growth hormone receptor signaling pathway and nitric oxide biosynthetic process.

CONCLUSIONS

Maternal MET supplementation can reduce the incidence of IUGR and increase the weaning litter weight of piglets, which may be associated with better intestinal function and methylation status.

Dietary bile acid supplementation in weaned piglets with intrauterine growth retardation improves colonic microbiota, metabolic activity, and epithelial function

BACKGROUND

Intrauterine growth retardation (IUGR) is one of the major constraints in animal production. Our previous study showed that piglets with IUGR are associated with abnormal bile acid (BA) metabolism. This study explored whether dietary BA supplementation could improve growth performance and colonic development, function, microbiota, and metabolites in the normal birth weight (NBW) and IUGR piglets. A total of 48 weaned piglets (24 IUGR and 24 NBW) were allocated to four groups (12 piglets per group): (i) NBW group, (ii) NBW + BA group, (iii) IUGR group, and (iv) IUGR + BA group. Samples were collected after 28 days of feeding.

RESULTS

The results showed that dietary BA supplementation increased the length and weight of the colon and colon weight to body weight ratio, while decreased the plasma diamine oxidase (DAO) concentration in the NBW piglets (P < 0.05). Dietary BA supplementation to IUGR piglets decreased (P < 0.05) the plasma concentrations of D-lactate and endotoxin and colonic DAO and endotoxin, suggesting a beneficial effect on epithelial integrity. Moreover, dietary BA supplementation to NBW and IUGR piglets increased Firmicutes abundance and decreased Bacteroidetes abundance (P < 0.05), whereas Lactobacillus was the dominant genus in the colon. Metabolome analysis revealed 65 and 51 differential metabolites in the colon of piglets fed a diet with/without BA, respectively, which was associated with the colonic function of IUGR piglets. Furthermore, dietary BA supplementation to IUGR piglets upregulated the expressions of CAT, GPX, SOD, Nrf1, IL-2, and IFN-γ in colonic mucosa (P < 0.05).

CONCLUSIONS

Collectively, dietary BA supplementation could improve the colonic function of IUGR piglets, which was associated with increasing proportions of potentially beneficial bacteria and metabolites. Furthermore, BA shows a promising application prospect in improving the intestinal ecosystem and health of animals.

Factors Influencing Proteolysis and Protein Utilization in the Intestine of Pigs: A Review

Pigs are among the most important farm animals for meat production worldwide. In order to meet the amino acid requirements of the animals, pigs rely on the regular intake of proteins and amino acids with their feed. Unfortunately, pigs excrete about two thirds of the used protein, and production of pork is currently associated with a high emission of nitrogen compounds resulting in negative impacts on the environment. Thus, improving protein efficiency in pigs is a central aim to decrease the usage of protein carriers in feed and to lower nitrogen emissions. This is necessary as the supply of plant protein sources is limited by the yield and the cultivable acreage for protein plants. Strategies to increase protein efficiency that go beyond the known feeding options have to be investigated considering the characteristics of the individual animals. This requires a deep understanding of the intestinal processes including enzymatic activities, capacities of amino acid transporters and the microbiome. This review provides an overview of these physiological factors and the respective analyses methods.

Differences in Intestinal Barrier Development between Intrauterine Growth Restricted and Normal Birth Weight Piglets

Simple Summary

Animals with intrauterine growth restriction (IUGR) are defined as neonates born at term but with low birth weight and a characteristic shape of the head. A number of structural and functional modifications in the IUGR intestine affecting its digestive and absorptive function and impairing intestinal barrier function have been reported in the past. Far less is known about the immune system in the gut of IUGR pigs. Therefore, the aim of the present study was to evaluate the structures of the immune system of the gut mucosa in IUGR neonates. We found that the immune deficiency in the gut mucosa that results from restricted intrauterine development occurs at postnatal day (PD) 7, but it disappears thereafter within a week. However, all examined IUGR piglets had an increased number of intraepithelial leukocytes in the gut mucosa on PD 14. We have shown that the immune system of the gut of IUGR piglets is able to quickly compensate for the immunological deficiency postnatally and hardly shows any morphological disabilities in later life.

Abstract

Intrauterine growth restricted (IUGR) piglets are born at term but have low birth mass and a characteristic shape of the head. Impaired general condition, especially in intestinal function, leads to an increase in the occurrence of diarrhoea and high mortality in the first days of life. So far, the mechanical and immunological gut barrier functions in IUGR are poorly understood. The aim of this study was to microscopically evaluate the early postnatal changes in the gut mucosa occurring in IUGR piglets. Whole-tissue small intestine samples were collected from littermate pairs (IUGR and normal) on postnatal day (PD) 7, 14 and 180 and analysed by light microscopy. We found that in the IUGR piglets, the percentage of intraepithelial leukocytes was reduced in the duodenum on PD 7, but it increased in the proximal and middle jejunum both on PD 7 and PD 14, which suggested the development of an inflammatory process. The number of goblet cells was also reduced on PD 14. The average size of the Peyer’s patches in the distal jejunum and ileum showed significant reduction on PD 7 as compared to normal pigs; however, on PD 14, it returned to normal. On PD 180, we did not find any differences in the measured parameters between the IUGR and the normal pigs. In conclusion, we found that in one-week-old IUGR pig neonates, the gut barrier and the immune system structures display signs of retarded development but recover within the second postnatal week of life.

Transcriptome Differences Suggest Novel Mechanisms for Intrauterine Growth Restriction Mediated Dysfunction in Small Intestine of Neonatal Piglets

Impaired intestinal function is frequently detected in newborns with intrauterine growth restriction (IUGR), whereas the mechanism between transcriptome profiles and small intestinal dysfunction is still unclear. Therefore, this study was conducted by using IUGR neonatal piglets to uncover the mechanism underlying intestinal dysfunction. Neonatal piglets with IUGR and normal birth weight (NBW) were sacrificed at birth. Transcriptomic sequencing was performed on jejunum samples and generated 18,997 and 17,531 genes in NBW and IUGR groups, respectively. A total of 10 differentially expressed genes (DEGs) were identified; of note, only seven were mapped to the genome reference database, with two up-regulated (HSF4 and NR1H4; heat shock transcription factor 4 and nuclear receptor subfamily 1 group H member 4, respectively) and five down-regulated (SLC35C1, BTNL3, BPI, NLRP6, and SLC5A8; Solute carrier family 35 member C1, butyrophilin like 3, bactericidal permeability increasing protein, NLR family pyrin domain containing 6, and solute carrier family 5 member 8, respectively). Combining an enrichment analysis and reverse transcriptase–quantitative polymerase chain reaction validation of DEGs, our results proved the lipid metabolism disorder, intestinal dysfunction, and inflammatory response in IUGR piglets. Here, IUGR piglets presented lower concentration of glucose and triglyceride and higher concentration of total cholesterol and low-density lipoprotein cholesterol in plasma, compared with NBW piglets. Histological analysis revealed decreased mucins and increased apoptosis in both jejunum and ileum for IUGR piglets. Collectively, we found that IUGR induced intestinal dysfunction by altering lipid metabolism, intestinal barrier, and inflammatory response in neonatal piglets at birth, which provides new insights into the prevention and treatment of IUGR that protects against metabolic disorders and inflammatory-related diseases.